When amphistomatic, the stomata were more abundant on the abaxial surface.
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The leaves are generally amphistomatic, with more stomata present on the abaxial surface.
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Sori acrostichoid (covering the entire abaxial surface of the leaf); Paraphyses absent. Spores monolete.
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Adaxial and abaxial midveins of one pinnule also show different widths, epidermal morphologies, and differing degrees of cutinization.
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Dead leaf sheaths persist at the base of the grass. The erose ligules measure . The conduplicate leaf blades are in diameter, with glabrous abaxial surfaces and scabrous adaxial surfaces. The abaxial sclerenchyma is composed of three to seven strands that form a continuous band and the adaxial sclerenchyma is absent.
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The mine has the form of an abaxial, oval, blotch-mine situated close to the base of the leaflet.
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D, E, oblique abaxial view of fertile units showing a bract with lateral segments and basal pendulous sporangia. F, side view of a fertile unit from Fig. 28 illustrating a bract with distal segment (arrow), lateral segments and basal sporangia. In side view, it is clear that many pendulous sporangia are abaxially attached at the base of a bract (Figs 28, black arrow, 39, arrow, 42F). It is also the case in abaxial (Figs 29, lower arrow, 37, arrow, 42B, arrow, 42C) and oblique abaxial (Figs 35, 36, black arrow) views of a bract.
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Leaves have pointed ends and are densely silvery or golden sericeous on the abaxial side. The species has not been cultivated.
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In adaxial view, about 2.0 mm above the attachment point to the strobilar axis, the bract blade possesses a linear depression (Fig. 42A, arrow 3) indicating the position where the abaxial sporangia were once attached. Corresponding to this example, abaxial sporangia are pendulous at the bract 3.3 mm away from the node of the strobilar axis (Fig.
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The establishment of leaf dorsiventrality is important since the dorsal (adaxial) surface of the leaf is different from the ventral (abaxial) surface.
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The tip of the teeth is opaque. The stomata are restricted to the underside (or abaxial surface), and are of the anomocytic type.
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Revolute vernation is the opposite of involute vernation: the margins of the leaf are rolled up towards the under (abaxial) surface of the leaf.
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However, the most characteristic symptom is the formation of enations on the abaxial, i.e. downy, leaf side. Enations are derived from the cells of vascular bundles undergoing hyperplasia.
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In the epidermis of third-year leaves, the densest silica deposition was observed in silica cells of both the adaxial and abaxial epidermises as in first-year leaves.
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Rotafolia songziensis D.-M. Wang, Hao & Q. Wang gen. et comb. nov. Fig. 35. Oblique abaxial view of two fertile units. Hu-B2. Scale bar = 5 mm. Fig. 36.
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28 Apr 2012. . No hair abaxial of sepal. The flower is hermaphroditic. The style is 3–10 cm long and remains attached to the achene, acting as its wings.
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The flat and conduplicate leaf blades are involute or convolute and are sometimes glaucous or pruinose. The abaxial surfaces of leaf blades are glabrous or scabrous and occasionally pubescent or puberulent. The adaxial surfaces of leaf blades are typically scabrous, though occasionally are hirsute or puberulent. The abaxial sclerenchyma tissue forms longitudinal strands that vary in presence from the margins and opposite of the midvein to adjacent to some or every lateral vein.
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Fruits plump, often longitudinally ribbed, sometimes flattened, rarely abaxially keeled, abaxial wings absent, lateral wings absent, glands often present.Lot H., A. & A. Novelo Retano. 1994. 234. Alismataceae. 6: 3–8.
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Abaxial view of elongate sporangia attached to base of an indistinct bract at the same level. Hu-21. Scale bar = 2 mm. Fig. 32. Anisotomous division of two fertile axes with terminal strobili.
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Once the leaf primordial cells are established from the SAM cells, the new axes for leaf growth are defined, one important (and more studied) among them being the abaxial-adaxial (lower-upper surface) axes. The genes involved in defining this, and the other axes seem to be more or less conserved among higher plants. Proteins of the HD-ZIPIII family have been implicated in defining the adaxial identity. These proteins deviate some cells in the leaf primordium from the default abaxial state, and make them adaxial.
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It is believed that in early plants with leaves, the leaves just had one type of surface - the abaxial one. This is the underside of today's leaves. The definition of the adaxial identity occurred some 200 million years after the abaxial identity was established. One can thus imagine the early leaves as an intermediate stage in evolution of today's leaves, having just arisen from spiny stem-like outgrowths of their leafless ancestors, covered with stomata all over, and not optimized as much for light harvesting.
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The abaxial surface is heavily coated in fine white hairs, and occasionally the adaxial surface will also have a sparse coating of white hairs. Abaxial leaf surface of P. bicolor Flowering occurs in spring. The attractive flowers typically occur at the nodes, and may be solitary, terminal or occur in small groups. The flowers are bell shaped, and the perianth consists of 5 sepals, which are 5-6mm long and slightly curve inwards at the apex, the lower surface is coated in fine white hairs.
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Orites acicularis has evolved a number of characteristics to assist with protection from solar radiation in excess of its photosynthetic requirements. Two such adaptations are its abaxial pseudohypodermis and its bundle sheath extensions. Bundle sheath extensions are formed when sclerenchyma and/or collenchyma cells around a bundle sheath extend to both the adaxial and abaxial epidermis layers of a leaf. The evolution of these bundle sheath extensions in species restricted to open vegetation in the family Proteaceae suggests that it is a recurring adaptation to provide protection against the high levels of solar radiation present.
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Sometimes it will cause galls and lesions. In the spring, there are yellow spots on the upper portion of the leaf and during the Spring and Summer there are orange spores on the abaxial surface of the leaf.
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Dotted lines indicate projections representing lateral segments preserved under bract. C, abaxial view of a fertile unit from Fig. 37 showing a bract bearing lateral segments and basal sporangia. Dotted lines indicate projections representing lateral segments preserved under bract.
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The Orites-type abaxial pseudohypodermis is defined as multiseriate, elongate sclerids forming a reticulum around the sub-stomatal cavities (Jordan et al. 2005) and acts as a further barrier to solar radiation that lies just below the cuticle of the plant.
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Along the entire lamina of Lepidophylloides, a single vascular bundle is bordered by shallow grooves on the abaxial surface. Stomata are sunken in pits aligned in rows parallel to these grooves. A hypodermal zone of fibers surrounds the vascular bundle of the leaf.
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Stomata therefore play the important role in allowing photosynthesis without letting the leaf dry out. In a typical leaf, the stomata are more numerous over the abaxial (lower) epidermis than the adaxial (upper) epidermis and are more numerous in plants from cooler climates.
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A stipule is considered "spiny" if they are long and pointy. These are generally used to deter animals. A stipule is considered to be "abaxial", "counter" or "leaf opposed" if it's located on the opposite side to where the leaf meets the stem.
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The calyx is actinomorphic or nearly so, and not accrescent as in some related genera. The corolla is blue, purple, or white, (rarely yellow), and 5-lobed. The abaxial lobe is often larger and different in color. The four stamens are long-exserted.
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The adaxial and abaxial surface of the leaf is covered with yellowish or purplish spines that grow from purple wart-like structures. In some cases they are covered with bristles. The upper leaves are smaller and bract-like. "Meconopsis horridula" has deciduous leaves.
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White arrows indicating fertile units in abaxial view, black arrows two fertile units enlarged in Fig. 28. Hu-19. Scale bar = 1 cm. Fig. 28. Higher magnification of two fertile units from Fig. 27 showing bracts in side view with elongate lateral segments.
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White arrows indicating distal segment of bract, black arrow sporangia at base of bract. Hu-19. Scale bar = 2 mm. Fig. 29. Bract in abaxial view showing lateral segments (upper arrow) and basal sporangia (lower arrow). Hu-A1. Scale bar = 2 mm.
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R. piliferus on the other hand has sepals that are hairy on both the adaxial and abaxial surfaces. It is a robust, summer-green, rhizomatous plant. The plant has numerous branched rhizomes. The rhizomes are fleshy, stout, and 10–12 mm in diameter.
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Leaf margins are entire, minutely ciliolate, and flat to slightly recurved. Prominent venation can often be seen on the abaxial sides of the leaves (3- to 5-veined). ;Inflorescence: A solitary terminal raceme, with 8–16 flowers, ranging from 10–30 mm in length.
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Abaxial view of a single fertile unit beside a strobilar axis showing bract bearing marginal segments and basal sporangia (arrow). Hu-B1. Scale bar = 2 mm. Fig. 38. Higher magnification of a fertile unit in Fig. 30 (lower arrow) attached to a strobilar node.
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Neuwiedia has three fertile, abaxial (= facing away from the stem) anthers, while Apostasia has two fertile abaxial anthers and a filamentous staminode (= a sterile stamen). Plants with mealy or paste-like pollen, which ordinarily are not aggregated into pellets, called pollinia, with two or three fertile long anthers, leaves with sheathing bases, elongated staminode and labellum similar to the petals. These primitive features make them, according to some authorities, not true orchids but rather ancestors of modern orchids. However, more recent studies indicate that many of their differences with the other orchids were not inherited from a common ancestor with orchids, but arose within the stem group of apostasioid orchids.
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Leaf sheaths are glabrous or pilose with hairs long, and lack auricles. The membranous and glabrous ligules are long. Leaf blades are long and wide, with an adaxial surface covered with hairs up to long and a glabrous abaxial surface. Margins are smooth or slightly serrated.
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Bright violet flowers are about long with the stamens exerted. Tillandsia caput-medusae does not have any free water retention in its overlapping leaves because its abaxial and adaxial leaf bases provides trichomes which coats the leaves. The significance of trichome is to enhance leaf permeability.
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It is also used for anthocyanin study experiments, especially with reference to abaxial and adaxial anthocyanic concentration. A recent study has revealed honeycomb-like microstructures on the taro leaf, which makes the leaf superhydrophobic. The measured contact angle on this leaf in this study is around 148°.
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Phyllocnistis drimiphaga is a moth of the family Gracillariidae. It is known only from cloud forests above 2000 m in Cordillera de Talamanca and Central Conservation Area in Costa Rica. 1=Life history of Phyllocnistis drimiphaga. A Leaf mines on abaxial side of leaf surface with white square enclosing early mine, arrow pointing to pupal cocoon fold B close-up view of early mine, arrow pointing to egg shell remains C same as figure B, but showing frass pattern (photo taken with sunlight projecting through the leaf from behind) D nearly mature old mine on adaxial side E nearly mature old mine on abaxial side (photo taken from adaxial side) F opened mine showing mature sap-feeding larva in situ G opened young pupal cocoon fold, showing cocoon-spinning larva in situ H pupal cocoon fold on adaxial mine I opened cocoon fold showing pupa in situ (dorsal view) J protruded and attached pupal shell (arrow) on pupal cocoon fold on abaxial leaf mine K opened cocoon pupal fold on adaxial mine showing Ageniaspis cocoons in situ.
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Structurally, the flower of P. lasianthos is thought to be designed to attract insects as it has a white to mauve corolla, shallow and wide floral tube, and a large abaxial lobe. However, pollinators of mint bushes in general are poorly known. Birds have been recorded visiting the flowers.
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The upper portion of the scape and the abaxial surface of the sepals are covered with white woolly non-dendritic hairs. Its roots are fibrous. Drosera derbyensis grows in sandy soils in floodways or near rock outcrops from Derby to Beverley Springs in the Kimberley region.Lowrie, A. 1996.
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Pandanaceae includes trees, shrubs, lianas, vines, epiphytes, and perennial herbs. Stems may be simple or bifurcately branched, and may have aerial prop roots. The stems bear prominent leaf scars. The leaves are very long and narrow, sheathing, simple, undivided, with parallel veins; the leaf margins and abaxial midribs are often prickly.
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The young skink will often climb on the abaxial area of the female or male for protection and security, just as in the case of the Solomon Islands skink (Corucia zebrata).Jones,Schnirel ;(2006). Subspecies comparison of the Genus: Corucia. Polyphemos, Florence, South Carolina U.S.A., Volume 4, Issue 1. May.
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Their leaves are borne in dense, evergreen rosettes. They are entire, have short petioles and lack stipules. They have a single wax-secreting trichome in the epidermal pits and glands on the abaxial surface. The flowers are small with a basally connate corolla, that are imbricate or rolled up lengthwise.
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23 showing lateral fertile units consisting of a bract with segments and sporangia attached at the same level. White arrows indicating elongate sporangia in abaxial view, black arrows distal segment of bract. Hu-18. Scale bar = 5 mm. Fig. 25. Strobilus bearing up to 16 whorls of fertile units. Hu-23.
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The bracts are elongate-cuneate and have prominent marginal fringes; sporangia are attached to the abaxial surface at the base of each brac. Although R. songziensis closely resembles H. verticillatum with its external axis morphology, leaf shape, and structure of the primary xylem. However, the two forms differ in strobilus morphology.
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These tropical ferns are the most widespread living lineage of Gleicheniales. Their rhizomes have a "vitalized" protostele or in some taxa a solenostele. The leaves are indeterminate, with pseudodichotomously forked leaves except in Stromatopteris, and free veins. The sori are abaxial but not marginal and carry 5–15 exindusiate round sporangia each.
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Corollae have five mostly unequal petals, and the anterior petal is larger and often spurred. Plants have five stamens with the abaxial stamen often spurred at the base. The gynoecium is a compound pistil of three united carpels with one locule. Styles are simple, with the ovary superior and containing many ovules.
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It is a common small tree with opposite leaves that are dark green on the adaxial (upper or dorsal) leaf surface and lighter on the abaxial (lower or ventral) surface and oblanceolate with a rounded or obtuse apex. The specific epithet ', Latin for "fetid" refers to the unpleasant scent of the flowers.
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More specifically, the abaxial surface of the sepal is moderately to densely covered in fine, pilose hair. The adaxial surface of the sepal is glabrous on the proximal part and sparely hairy to glabrous near the distal part. The stems hold one flower apiece. These features distinguish it from the R. piliferus.
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These plants are described by Hueber as having monopodially branched stems, that are unridged, spinous and circinately tipped. The sporangia are described as round in abaxial view, and oval in lateral view. These sporangia are formed laterally and singular on short stalks. The sporangium split along convex margins into equal valves in a trilete fashion.
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These longitudinal strands occasionally merge into interrupted or continuous bands. Bands of confluent strands that reach veins are known as "pillars". The adaxial sclerenchyma tissue sometimes forms strands that are opposite or extend to epidermal veins. Some strands form "girders" together with the abaxial sclerenchyma tissue that connect epidermides at some or all veins.
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The plant lacks auricles. The membraneous and erose ligules are long and are glabrous or pubescent. The grey-green leaf blades are long and wide, with a pubescent adaxial surface and an abaxial surface pubescent with hairs about one quarter the length of those on the adaxial surface. The leaf margins are smooth or serrated.
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Characteristic features of this plant include dark green leaves with a glossy adaxial surface and purple abaxial surface. These leaves are circular with deeply divided lobes. Their basal leaves are deciduous. The stem of this species can be used as a distinguishing feature as it has reflexed hairs that are pressed towards the stem.
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It can be distinguished from the similar-looking Vaccinium corymbosum by its stems and abaxial leaf surfaces are pubescent with dingy hairs, and its dark colored fruit that lacks a glaucous coating. In addition it has an earlier bloom time, producing flowers in early spring. It is sometimes considered a synonym of Vaccinium corymbosum.
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Aglaomorpha rigidula growing on rocks in Australia. The fertile foliage fronds are large and dark green, the smaller brown sterile nest fronds are clustered at their bases. Sori on the abaxial surface of the foliage frond of Aglaomorpha quercifolia. Basket ferns are characterized by the presence of two types of fronds, fertile foliage fronds and sterile nest fronds.
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Ericoideae is a subfamily of Ericaceae, containing nineteen genera, and 1,790 species, the largest of which is Rhododendron, followed by Erica. The Ericoideae bear spiral leaves with flat laminae. The pedicel is articulated and the flowers are pendulous or erect, and monosymmetric, with an abaxial median sepal. The carpels are free and the anthers lack appendages.
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The leaves are glossy green on the upper (abaxial) surface, and dull grey on the lower (adaxial) surface. It has gained the Royal Horticultural Society’s Award of Garden Merit. The specific epithet fargesii commemorates Paul Guillaume Farges (1844–1912), a French missionary and botanist who sent many plant specimens back to Europe, where they were unknown at that time.
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Asplenium ceterach (syn. Ceterach officinarum) is a fern species commonly known as Rustyback. It is characterised by a short rhizome which gives rise to several green fronds that have a pinnated lamina with trichomes on the abaxial (lower) surface, but not the adaxial (upper) one. These trichomes (hairs) are orange-brown in colour, hence the name "rustyback".
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The petals and staminodes are usually yellow to red. The three carpels are at a constant under (syncarp) ovary adherent which has a soft-spiky surface and many central angle constant ovules contains. The pollen is deposited on the abaxial (off- axis) surface of the stylus. The pollination mechanism is very specialised and the pollination is done by insects.
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The leaves are long with lobed or pinnately- divided edges. The abaxial surface (underside) of the leaf is somewhat hairy. At the top of each branch of the stem is an inflorescence of one to several flower heads, each rounded, covered in spiny phyllaries, and bearing many threadlike, purple or pink disc florets. Each flowerhead is around across.
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Line drawings of fertile units. A, adaxial view of a bract from Fig. 33. Arrow 1 showing a distal segment of bract, arrow 2 lateral segments of bract, arrow 3 depression marking position of sporangial attachment, arrow 4 vertical depressions possibly representing epidermal cells. B, abaxial view of a bract showing lateral segments and basal pendulous sporangia (arrow).
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The bases of the primary branches contain between 2 and 5 compressed internodes and secondary branching does not occur at these basal areas. The foliage leaves are deciduous and their blades are typically 5 to 20 cm long by 0.8 to 2 cm wide. The blades have rounded bases and are chartaceous (i.e. paper-like). Their abaxial surfaces (i.e.
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Multiple stipes (25–40), 9–46 cm long, with fronds up to 65 cm in length, arise from long creeping rhizomes 2.5–3.5 mm in diameter. Scaly rounded pinnules 1–2 mm across, with flat adaxial surfaces and strongly recurved into an abaxial pouch, hold sori of 2–4 sporangia. G. abscida growing in its typical exposed alpine habitat.
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The undersides of the leaves (abaxial surface) sometimes exhibited parallel longitudinal ridges and grooves. The free part of the lamina (the leaf blade) was about half the length of the leaves. These fossils are found together with two types of highly distinctive cones (presumed to be female) that show affinities to both Araucariaceae and Cupressaceae (cypresses). However, they have not been described.
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Pollen strobili of Pinophyta are similar to those of cycads (although much smaller) and Ginkgoes in that they are composed of microsporophylls with microsporangia on the abaxial surface. Seed cones of many conifers are compound strobili. The central stem produces bracts and in the axil of each bract is a cone scale. Morphologically the cone scale is a reduced stem.
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The base of the leaf is rigid and nearly sessile, attached to the stem with a short and flat petiole. Dimensions are roughly 25–40 mm long and 8–12 mm wide. Leaf margins are entire, and flat to slightly recurved. Prominent venation can be seen on the abaxial sides of some leaves (3-5 veined), but this is indistinct on others.
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They are evergreen monoecious, hermaphrodite, trees or rarely bushes. Leaves lax at the apex of the branches, without papillae on the abaxial epidermis of the leaves. The leaves are alternate or opposite but rarely opposite, entire, subcoriaceous in some species of Central America as Nicaragua, glabrous on the upper, glabrous or pubescent on the underside, pinnatinervium. Flowers in panicles terminating in a top.
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The erect, slender and pungent shrub typically grows to a height of . It has glabrous to sparsely haired and yellow-ribbed branchlets. Like most species of Acacis it has phyllodes rather than true leaves. The pungent and g;abrous, evergreen phyllodes have an inequilateral and obtriangular shape that are in length and a width of with a midrib near the abaxial margin.
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The stalks are covered with orange-brown scales. On the abaxial surface of the mature blade 5 to 6 sori develop in two rows. When the spores ripen in August to November, the indusium starts to shrivel, leading to the release of the spores. This species hybridises easily with Dryopteris affinis (scaly male fern) and Dryopteris oreades (mountain male fern).
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The shrub typically grows to a height of . Like most species of Acacia it has phyllodes rather than true leaves. The evergreen, glabrous or hairy phyllodes appear crowded on the branchlets. The rigid and pungent phyllodes have an inequilateral to shallowly triangular shape with a length of and a width of and also has a midrib near the abaxial margin.
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The flowers are showy, yellow, and open singly and die rapidly, but are immediately followed by another. The species becomes dormant during winter, shrinking to a centipede-like rhizome without roots. In spring it produces paddle-shaped leaves that appress to the soil when fully formed, similar to water-lily pads. The abaxial leaf surface has a spongy white texture.
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Vegetative phase change is the juvenile-to-adult transition in plants. This transition is distinct from the reproductive transition and is most prolonged and pronounced in woody species. Manipulating phase change may be an important avenue for plant improvement. In the model plant Arabidopsis thaliana, vegetative phase change is relatively subtle: leaves become more curled, with an increased number of abaxial trichomes, and increased serration.
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The leaves of A. xizangensis are simple. Leaflets are typically between 23 – 24 cm long, broadly ovate, cordate at their bases, rounded and obtuse at their apexes, and finely-toothed on their margins. Each has 5 basal veins, and 4 or 5 pairs of lateral veins. Smaller veins are barely noticeable on the leaf's upper (adaxial) surface, while being slightly prominent on the under (abaxial) side.
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The mature larval case is in length and wide, smooth with banding that follows the length of the case. The case widens slightly at both ends. Case-making larvae were collected on the abaxial surface of old fronds of Cibotium glaucum. The habit of residing in old tree fern fronds, still attached to the stump, is typical of several purse case species including Hyposmocoma filicivora.
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Fern fronds often bear sporangia, where the plant's spores are formed, usually on the underside (abaxial surface) of the pinnae, but sometimes marginally or scattered over the frond. The sporangia are typically clustered into a sorus (pl., sori). Associated with each sorus in many species is a membranous protective structure called an indusium, which is an outgrowth of the blade surface that may partly cover the sporangia.
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Aristotelia serrata leaves have distinguishable traits. Leaves are thin, deeply and sharply serrated, light or dark green on adaxial surface, often pinkish green on abaxial surface, veins distinct on both surfaces, size between 5-12 x 4–8 cm. The leaves, are disposed in opposite or subopposite pairs. They have drawn-out, pointed tips and prominent veins forming an obvious net-like vein pattern on both sides.
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The corolla lobes show glandular hairs at the abaxial surface. Helichrysum species are used as food plants by the larvae of some Lepidoptera species including the bucculaticid leaf-miners Bucculatrix gnaphaliella (which feeds exclusively on Helichrysum arenarium) and Bucculatrix helichrysella (feeds exclusively on H. italicum) and the Coleophora case-bearers C. caelebipennella, C. gnaphalii (feeds exclusively on H arenarium) and C. helichrysiella (feeds exclusively on H. italicum).
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They are ciliate, meaning they have small hairy projections emerging from the margins of the leaf, while the apices, or tips of the leaves, are acuminate, meaning they taper to a point. The adaxial (i.e. upper) surfaces of the leaves are nearly hairless or sparsely hairy, while the abaxial (i.e. lower) surfaces are sparsely hairy with the veins being more villous, or covered in shaggy hairs.
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On the abaxial surface, leaves are a pale greyish colour and have prominent veins covered with fine, greyish-brown, dense, sessile star-shaped hairs. Inflorescence consists of large panicles with pale yellow, cream, or greenish coloured flowers. Flowers are also small, exist in terminal clusters, have no petals, and have ovaries which are practically inferior. The sepals are persistent, bracts deciduous, and the operculum is membranous.
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Elaphoglossum pattersoniae is a very rare species of fern that is native to Peru and Bolivia. It is very close to E. guamannianum, but is smaller in size, its blade apex is acute-obtuse, it lacks dark arachnidoid scales on its abaxial costa and has fewer blade scales.Mickel, John T. "Three new species of Elaphoglossum from Peru." American fern journal 80.3 (1990): 110-112.
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Monotoca glauca is an evergreen, densely branched shrub or small tree with slender branches, often 2–3 m tall. Leaves are similar to Cyathodes glauca, however are not in whorls. Venation tends to be spreading or palmate, characteristic of the genus. Leaves are elliptic with a point, and are usually 1.5 cm long, with a yellowish- green, glabrous adaxial surface, and glaucous abaxial surface.
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R. acraeus has been mistaken for R. piliferus but minute morphological differences distinguish each plant as its own species. R. acraeus has finely crenate (wavy-toothed) leaves and bract margins. The plant also has a glabrous peduncle and 6 to 7 sepals that are glabrous on the adaxial surface and hairy on the abaxial surface. Glabrous means that it is smooth, glossy, and not hairy.
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The inflorescence is a solitary, showy flower with indistinguishable petals and sepals. Sepals range from six to many; stamens are numerous and feature short filaments which are poorly differentiated from the anthers. Carpels are usually numerous, distinct, and on an elongated receptacle or torus. The fruit is an etaerio of follicles which usually become closely appressed as they mature and open along the abaxial surface.
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The upper surface of the petiole is glabrous, but the margins and lower surface possess hairs similar to those of the abaxial leaf surface. One or two racemose inflorescences are produced per plant and are usually long. Approximately 12 flowers are found on one inflorescence with each white or pink flower held on a 3–5 mm long pedicel. The scape, inflorescence, and sepals are sparsely covered in white hairs.
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It has imparipinnate leaves, with 9 - 15 toothed, oblong leaflets, which are approximately 2 –11 cm long. The adaxial surface of the leaves is dark green and shiny, and the abaxial surface is hairy and glaucous green in colouration. The rachis of the leaves is often red. The scape is 10 – 15 cm long and bears a globular, terminal inflorescence, of 20 – 25 mm diameter, with 70 – 100 flowers.
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Circinate vernation is also typical of the carnivorous plant family Droseraceae, for example see this photo of Drosera filiformis. It is also seen in the closely related genera Drosophyllum and Triphyophyllum, and in the much more distantly related Byblis; however in these three genera, the leaves are coiled outwards towards the abaxial surface of the leaf (reverse circinate vernation): this appears to be unique to these three plants among the angiosperms .
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H. barkerae tends to grow in clumps in heavy clay soils in the shelter of rocks or shrubs. It has pale to deep pink flowerheads. The two leaves (occasionally one) last from May to October, are narrowly ligulate to near elliptic, are almost erect and appear after the flowers which bloom between March and April. The abaxial surfaces of the leaves are conspicuously barred with dark green and maroon.
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It is a lianescent subshrub or erect perennial herb around tall. Its rhizome is around thick; its stems are erect, with numerous deflexed stinging hairs, approximately long. Its leaves are opposite, interpetiolar stipules united in pairs but deeply incised, about long and wide, without conspicuous cystoliths and with scattered, white simple trichomes along the margins. Petioles are long, abaxial surface with scattered pubescence on the veins and with scattered stinging hairs.
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Monotoca scoparia is a lignotuberous shrub that grows usually between 30–120 cm high. The alternating leaves are erect and prickly, and narrowly oblong to elliptic in shape. Leaves are 0.6-2.2 cm long and 1–4 mm wide. The adaxial (upper) surface of the leaf is dark green in colour and the abaxial (lower) surface in a pale green to whitish colour, with 3-5 prominent veins.
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Symptoms on Tomato Leaf. Photograph provided by Elizabeth Bush, Virginia Polytechnic Institute and State University. The tomato leaf mold fungus is a specific pathogen of tomato plant Lycopersicon, this pathogen has restricted host range (host specific pathogen) that only infects tomatoes, mainly in greenhouses. The symptoms of this disease commonly occurs on foliage, and it develops on both sides of the leaf on the adaxial and abaxial surface.
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Central spines have length up to about and are brownish-black in color. There are four central spines (4-5 per areole), where the lower central spine is white, abaxial central spines are tinged, is gray-purplish, angled, and strongly hooked and slightly contorted. Central spines are 1.2–3 cm long and 0.5–1 mm wide, curving towards the ground. The two lateral spines are flattened and thicker.
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The frond is light green when young, becoming darker green as it matures, and usually contains five blades arranged in a pentagonal fashion. The blades are bipinnately or tripinnately compound, and each of them is triangular and pointed. The abaxial side of the frond is covered by powdery farina, with a function that is still unclear. The color of the farina differs between species growing in different geographic locations.
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In ferns, sporangia are typically found on the abaxial surface (underside) of the leaf and are densely aggregated into clusters called sori. Sori may be covered by a structure called an indusium. Some ferns have their sporangia scattered along reduced leaf segments or along (or just in from) the margin of the leaf. Lycophytes, in contrast, bear their sporangia on the adaxial surface (the upper side) of leaves or laterally on stems.
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Gleichenia alpina is a common native ground-fern that grows in boggy alpine and subalpine vegetation. It has the typical Gleichenia foliage, which is repeatedly dichotomously divided before ending in pinnate laminas. The distinctive feature is deep pouches densely covered with hairs on the underside of the pinnules. Gleichenia alpina is characterised by comparatively short frond axes and the dense orange-brown (becoming pale) scales that obscure the abaxial surface of the lamina.
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Clethra scabra is a shrub or tree growing in habitats from in altitude, native to the eastern Andes and adjacent montane woodlands and Chaco of Brazil, Bolivia, Paraguay, and northwest Argentina. It is able to reach in height, and is known to flower during March. It bears simple ovate to elongate and slightly obovate leaves in length and in width. These leaves tend to bear stellate hairs, and have prominent veins upon their abaxial face.
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In leaves, the vascular bundles are located among the spongy mesophyll. The xylem is oriented toward the adaxial surface of the leaf (usually the upper side), and phloem is oriented toward the abaxial surface of the leaf. This is why aphids are typically found on the undersides of the leaves rather than on the top, since the phloem transports sugars manufactured by the plant and they are closer to the lower surface.
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The leaves can be described as having pinnate venation with obtuse or rounded leaf blade bases, rounded leaf apices, sub-entire blade margins, and glabrous surface. A leaf's abaxial surface is dull, pale and its adaxial surface is shiny, dark green with a leathery feeling upon touch. There is also sometimes white tissue that borders larger veins adaxially. The plant is evergreen and its leaves are persistent throughout all seasons unlike deciduous plants.
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Perhaps the most distinguishing feature of G. angustifolia is its leaves. G. angustifolia has an abaxial leaf surface that is covered in short, fine velvety hairs which is an uncommon trait among the genus Gustavia. In general the leaves are sessile but they can have petioles up to 30 mm long. The leaf blades tend to be narrow, having an oblong to oblanceolate shape, while the leaf bases are attenuate to acute in shape.
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The leafblades may be hairy or glabrous, canaliculate and marked with maroon spots and bars on the abaxial surface. The leaf margins, occasionally edged in red, are strongly crisped or crinkled, ranging from throughout their length, to near the base only. Flowers, appearing from March to May, and spathe valves are usually red, but occasionally pink. Fruits are up to 20 mm diameter, pink and pulpy when ripe, holding from one to four dark-red seeds.
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Begonia adamsensis is an endemic species of Begonia discovered in Adams, Ilocos Norte province, Luzon, Philippines occurring at an altitude of 308 m above sea level. The species broad-based leaves that are peltate, with a glabrous peduncle, an acuminate tip and nearly entire margin, resembled that of Begonia hernandioides. However, there are differences, in that B. hernandioides had red-colored stipule that is broadly ovate, the petiole and abaxial lamina is pubescent, and the peltate leaves are elliptic.
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The pectinate leaves are twisted at their petioles in opposite directions on each side of the shoot causing the adaxial sides of the leaves face up on one side of the shoot and down on the other side. The leaf blades are usually 15-25 millimeters long, 3-5 millimeters wide and ovate-lanceolate or ovate-elliptic in shape. Juvenile leaves are often larger. The narrow midrib of the leaf is conspicuous on the abaxial side.
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The species also has small (20 microns) irregular epidermal guard cells on the adaxial ("top") side of the leaf and bigger (24 microns) dome-shaped epidermal/guard cells on the abaxial side along with leaf stomata that are hemiparacytic (traits only shared with D. calycinum). The calyx is persistent, 2-3mm in size. The fruit 10-15 mm, not glaucous, loosely arranged. The plant flowers in Zhōngguó/China in March and April, fruiting from October to December. Var.
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Abaxial view of sporangia along vertically central area of strobilar axis indicating their attachment at the same level (marked by dotted line). A fertile unit consists of a bract and numerous sporangia. In adaxial view, the blade of the bract is attached to a strobilar axis and elongate wedge-shaped in outline (Fig. 33). On its surface, there are many linear depressions which may represent the remains of the epidermal cells (Figs 34, 42A, arrow 4).
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Puccinia thaliae is the causal agent of canna rust, a fungal disease of Canna. Symptoms include yellow to tan spots on the plant's leaves and stems. Initial disease symptoms will result in scattered sori (clustered sporangia), eventually covering the entirety of the leaf with coalescing pustulates. Both leaf surfaces, although more predominant on the underside (abaxial) of the leaf, will show yellow to brownish spore-producing these pustulate structures, and these are the signs of the disease.
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A vein is made up of a vascular bundle. At the core of each bundle are clusters of two distinct types of conducting cells: ; Xylem: Cells that bring water and minerals from the roots into the leaf. ; Phloem: Cells that usually move sap, with dissolved sucrose(glucose to sucrose) produced by photosynthesis in the leaf, out of the leaf. The xylem typically lies on the adaxial side of the vascular bundle and the phloem typically lies on the abaxial side.
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It is a dioecious shrub approximately tall, its shoots and adaxial leaf surfaces covered with scattered stalked glands less than half a millimetre long. Its petiole is long and wide, with its stipules well differentiated, united with the petiole for . Its adaxial surface is subglabrous, eglandular, while the abaxial surface has scattered stalked glands especially on its primary and secondary veins. Inflorescences are terminal on short lateral shoots (brachyblasts); racemes are pendent, and the peduncle is long, with scattered stalked glands.
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Ribes colandina is a dioecious shrub approximately tall; densely to moderately tomentose from simple, curly trichomes long and with scattered subsessile glands, especially on young shoots and the abaxial leaf surface. Its petiole is long, wide; its stipules well differentiated, united with the petiole for . Inflorescences are terminal on short lateral shoots (brachyblasts); racemes pendent with a -long peduncle. The flowers are narrowly cyathiform, with the calyx and corolla a very dark red, x in size, covered with simple hairs long.
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Buds are ellipsoid, red-brown, and resinous. Leaves (needles) are five per bundle (fascicle), sometimes four, spreading to ascending-upcurved, 4–9 cm long (rarely 10), 0.6-1.0 mm in diameter, straight, slightly twisted, pliant, dark green to blue-green, and persist 3–5 years. The upper surface ('adaxial' - facing toward the stem of the plant) is conspicuously whitened by narrow stomatal lines. The lower surfaces ('abaxial' - facing away from the stem of the plant) are without evident stomatal lines.
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The pungent shrub typically grows to a height of and has an open and spreading habit with sparely pilose and hairy branchlet with pungent stipules that are in length. Like most species of Acacia it has phyllodes rather than true leaves. The pungent, glabrous and evergreen phyllodes have an obtrinagular to obdeltate to shallowly obtriangular shape that are contiguous with the branchlet. The phyllodes have a length of and a width of and have a midrib near the abaxial margin.
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Adaxial leaf surface of P. bicolor Leaves are narrow, and vary in shape from being lanceolate to slightly ovate. They are typically 2–8 cm long and 5-18mm wide, margins are flat or distinctly recurved, with an obtuse to subacute apex. They are alternately arranged along the stem, and, as the name suggests, are most distinct in the contrasting colours of the leaf surfaces. The adaxial surface being a glossy dark green colour, and the abaxial surface being light green to silver-grey in colour.
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The epidermis serves several functions: protection against water loss by way of transpiration, regulation of gas exchange and secretion of metabolic compounds. Most leaves show dorsoventral anatomy: The upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. The epidermis tissue includes several differentiated cell types; epidermal cells, epidermal hair cells (trichomes), cells in the stomatal complex; guard cells and subsidiary cells. The epidermal cells are the most numerous, largest, and least specialized and form the majority of the epidermis.
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A hastula is a flap of tissue borne at the insertion of the blade on the petiole on the upper, lower, or both leaf surfaces Bifurcate fronds may also develop. The extinct Devonian seed plant Cosmosperma polyloba demonstrated the early evolutionary diversification of frond branching patterns, presenting both bifurcate and trifurcate types. Some ferns, like members of the group Ophioglossales have a unique arrangement -- such as a single fleshy or amorphous leaf. Adaxial (left) and abaxial (right) surfaces of a pinnate fern frond (Blechnum appendiculatum).
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Hoya bilobata is an evergreen perennial that is generally found trailing, but can have a climbing habit that grows to 24 inches or longer. H. bilobata can be considered either an epiphyte or a lithophyte. The H. bilobata leaves have a variable, sub- orbicular or broadly elliptic shape, with the leaf base being rounded to sub- acute and the leaf apex being obtuse-rounded. The adaxial surface of the leaves are a dull, olive-green colour with the abaxial surface being a lighter green.
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Like most members of the Lamiales the flowers are zygomorphic. The (B) inflorescences are terminal erect 15–30 cm long panicles of ~5 cm long flowers. (C) The thick fused calyx is covered by a brown hairy indumentum and the fused calyx tube is the same length as its calyx lobes, except in P. catalpifolia and P. elogata where the lobes are shorter than the calyx tubes. The corolla has 5 fused lobes with a shorter adaxial bilobed lip and a somewhat longer abaxial trilobed lower lip.
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The spreading and pungent shrub typically grows to a height of . It can have an intricate, sprawling or compact habit and has glabrous branchlets that are often covered in a fine white powdery coating and have spny stipules that are in length and shallowly recurved. Like most species of Acacia it has phyllodes rather than true leaves. The pungent, coraiceous and green dimidiate phyllodes are widest below or near or below the middle and are in length and in width with a midrib near the abaxial margin.
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L. nivalis also has 1–2 cauline leaves which are long; both leaf types are grass-like, flat, linear, straight and possess parallel veins. The leaf tips are obtuse, acuminate, involute, caducous and slightly swollen. Both the blade adaxial and abaxial surfaces are glabrous, with sparse, white, non-glandular hairs along the blade margins. The inflorescence of Luzula nivalis is congested in a single, dark, many-flowered head 0.8–1.0 × 0.6–0.9 cm in size; between 5–60 small flowers can be found in each inflorescence.
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It forms a boundary between the plant and the external environment. The epidermis serves several functions: it protects against water loss, regulates gas exchange, secretes metabolic compounds, and (especially in roots) absorbs water and mineral nutrients. The epidermis of most leaves shows dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. Woody stems and some other stem structures such as potato tubers produce a secondary covering called the periderm that replaces the epidermis as the protective covering.
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The blade bears a distal elongate segment (Figs 33, white arrow, 42A, arrow 1). At the lateral side of the blade near the strobilar axis, there are several lateral elongate segments that recurve toward the axis (Figs 33, black arrow, 42A, arrow 2). Possibly because of preservation, the other side of the blade lacks lateral segments. In abaxial view, lateral elongate segments are distinct on one side of the elongate wedge-shaped bract blade near the strobilar axis (Figs 29, upper arrow, 37, 42B, 42C).
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Leaf dimensions range from 5–30 mm long and 1.5–2.5 mm wide, and are observed to be simple, alternate and evergreen. Their shape is highly variable, commonly occurring as linear, narrow elliptic or narrow obovate but always exhibiting a spiky aristate apex. Leaf margins are flat to recurved, with the abaxial (lower) surface a darker shade than the adaxial (upper) surface. Leaf blades occur at right angles to the petiole, which is short and appressed to the stem, with pointed, soft, brown stipules occurring at the leaf base.
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It includes only a few species of small evergreen trees and shrubs species native to tropical South America.Kew World Checklist of Selected Plant FamiliesLissocarpa in IPNI, The International Plant Names Index Lissocarpa species share various characters with other members of Ebenaceae, e.g., the black color of roots and bark, extrafloral nectaries on abaxial leaf surfaces, a persistent calyx, unisexual flowers, biovulate carpels with pendulous ovules, and a similar wood anatomy producing a hard, dark heartwood timber similar to ebony. They are slow-growing trees found on a wide variety of soils and sites.
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Mothers lay their eggs in circular deposits on the abaxial (lower) side of leaves; eggs are "attached at a slight angle and covered with frass". The species goes through five instars in its life cycle, and the fifth instar and adult form were included as figures in Fink (1915). The developmental process from egg to adult takes about 20 days, the nymphal stage taking about 10 days. Fink noticed that the nymphs have spines, though he was not entirely sure why (more recent work has shed light on their function).
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Lemma is a phytomorphological term referring to a part of the spikelet. It is the lowermost of two chaff-like bracts enclosing the grass floret. It often bears a long bristle called an awn, and may be similar in form to the glumes—chaffy bracts at the base of each spikelet. It is usually interpreted as a bract but it has also been interpreted as one remnant (the abaxial) of the three members of outer perianth whorl (the palea may represent the other two members, having been joined together).
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They are linear-lanceolate in shape, distally gradually attenuate, i.e. tapering to a point at the end. Their outline is falcate, or sickle-like, to more or less straight and flat. The texture is somewhat leathery, but generally they are quite soft and flexible. The midvein is 0.2 to 0.5 mm wide on the abaxial surface, or underside, showing two broad and grey stomatal bands that are 0.8 to 2.1 mm wide with 13 to 24 rows of stomata, though the individual stomata are not readily visible to the naked eye.
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The rhizomes are often stout, creeping, ascending, or erect, and sometimes scandent or climbing, with nonclathrate scales at apices. Fronds are usually monomorphic, less often dimorphic, or sometimes scaly or glandular, but less commonly hairy. Petioles have numerous round, vascular bundles arranged in a ring, or rarely as few as three; the adaxial bundles are largest. Veins are pinnate or forking, free to variously anastomosing; the areoles occur with or without included veinlets; sori are usually round, acrostichoid (covering the entire abaxial surface of the lamina) in a few lineages; usually indusiate, or sometimes exindusiate.
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This species of Ribes is distinct form both R. andicola and R. colandina because of its ovate to elliptical leaves with a very poorly developed lateral lobe and its aberrant indument. The two latter species have leaves with pubescence on both the adaxial and abaxial surface and the adaxial leaf surface is matt green, whereas R. sanchezii has a shiny dark green upper leaf surface and pubescence abaxially restricted to the primary and secondary veins. Ribes sanchezii also has strongly resupinate fruits, whereas the fruits of R. andicola and R. colandina are pendulous.
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The shape of the ligule is awl-shaped and occurs singly. The leaves of S. apoda contain a cuticle layer on their adaxial surfaces and they do not have hairs on their abaxial surfaces. The internodes of S. apoda branches can be used to classify the branches as reproductive or vegetative, as the internodes are extended on vegetative branches. Selaginella apoda adventitious and primary roots contain a root cap at their tips, have the ability to branch when growing, are white, and possess root hairs, located in close proximity to the tips.
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The spindly, open and viscid shrub typically grows to a height of . It is sparingly branched with glabrous branchlets that become roughened by stem-projections the once held the phyllodes in place and setaceous stipules with a elngth of in length.. Like most species of Acacia it has pyllodes rather than true leaves. The tick and evergreen phyllodes are crowded on the branchlets and are patent to erect. The phyllodes have a linear shape and are straight to shallowly curved with a length of and a width of with a resinous midrib and abaxial nerves.
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The teeth are non-glandular and each primary tooth is supplied by a secondary vein and each subsidiary tooth by a secondary vein branchlet. The leaves are pinnately veined with a thin midvein from which the secondary veins alternately or oppositely branch off between 40 – 80°. There are between 7 and 13 secondary veins that run parallel to each other and curve upwards near the tips before terminating in the teeth. As the secondaries approach the margin they produce up to 7 branches from the abaxial side, each of which supply subsidiary teeth.
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The life cycle starts with the fungus overwintering as sclerotia on plants debris, in seeds and in soils as a saprophyte. Conidia also play an important role as a survival structure, once they are resistant to drying, and might survive up to one year in the absence of a susceptible host. When condition are favorable the sclerotia produce new conidia, which act as primary inoculum to infect plants. The conidia produce mycelium that infects the plant through stomata when humidity is 85% or higher and produce conidiophores on the abaxial leaf surface of infected leaves.
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Wheat is unusual among plants in having more stomata on the upper (adaxial) side of the leaf, than on the under (abaxial) side. It has been theorised that this might be an effect of it having been domesticated and cultivated longer than any other plant. Winter wheat generally produces up to 15 leaves per shoot and spring wheat up to 9Wheat Growth Guide and winter crops may have up to 35 tillers (shoots) per plant (depending on cultivar). Wheat roots are among the deepest of arable crops, extending as far down as 2m.
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As to Hamatophyton, each sporangiophore at the strobilar node bifurcates into two parts. The shorter part acts as a possible bract, the longer one results in two adaxially recurved long stalks, each of which terminates in an elliptical sporangium. Two sporangia are more or less parallel to the sporangiophore before bifurcation. In Rotafolia, however, each fertile unit of the strobilus has an elongate-cuneate bract that bears a distal segment and 10–18 lateral elongate segments. 6–10 elongate abaxial sporangia are pendulous at the base of the bract.
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Details of the suture are often useful in discriminating one species from another, for example, sometimes the suture is channeled. The suture also provides a sort of geographic marker from which one can refer to the positioning of patterning or sculpture, where that is relevant: for example some species have a darker or lighter subsutural band on the shell. When an angulation of the whorls occurs, the space between it and the suture above it (i.e. the abaxial edge of the sutural ramp) constitutes the area known as the "shoulder" of the shell.
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The leaves of a lateral shoot are further twisted at their petioles to form two pectinate rows in a horizontal plane around the shoot. The leaf petioles in Retrophyllum are uniquely twisted on the lateral shoots in opposite directions on each side of a shoot orienting the leaf blades with the adaxial or ventral surface upwards on one side of the shoot and the abaxial or dorsal surface upwards on the opposite side of the shoot. The leaf blade varies in shape from lanceolate to narrowly ovate. The leaves have conspicuous midribs and are amphistomatic with stomata present on both sides.
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Retrophyllum shoots have a distinctive morphology in which the leaves are in subopposite pairs, and twisted in such a way that the abaxial surface of one leaf is up, and in the other it is down. This feature, added to a distinctive epidermal morphology means that well-preserved specimens can be easily identified in the fossil record. The fossil record shows that Retrophyllum was present in the Cenozoic of Argentina, AustraliaHill, R.S. and Pole, M.S., 1992. Leaf and Shoot Morphology of Extant Afrocarpus, Nageia and Retrophyllum (Podocarpaceae) Species, and Species with similar Leaf Arrangement from Tertiary sediments in Australasia.
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It is unique in the subgenus because of its large leaves that are typically flat against the soil. Retentive mucilage-producing glands held on stalks – structures known as tentacles – appear on the margin of the lamina with shorter glands in the center of the leaf. The abaxial (underside) surface of the leaf is noticeably veined and sparsely covered with non-glandular white hairs. Petioles are oblanceolate and usually 10 mm long with varying widths: 2 mm near the center of the rosette, 3.5 mm near the center of the petiole, and 3 mm at the point of attachment to the lamina.
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The leaves are broadly linear in shape and measure about 5 cm long by 0.3 cm wide. They are abruptly pointed at the apex, leathery in texture and a bright matte yellowish-green on the upper-surface. The abaxial surface, or underside of the leaves, shows two broad, pale to silvery stomatal bands. Coloured plate from the book Flora Japonica, by Philipp Franz von Siebold and Joseph Gerhard Zuccarini The species is dioecious and the male plants are typically densely covered with pairs of flowers that are pale cream in colour, though they become brown with time, and globular in shape.
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Limnobium laevigatum is a floating aquatic plant, which can be mistaken for water hyacinth (Eichornia crassipes) due to their superficial similarity. Juvenile plants grow in rosettes of floating leaves that lie prostrate upon the water surface, a distinguishing character of the juvenile plant is the presence of spongy aerenchyma tissue upon the abaxial surface (underside) of the leaf. Mature plants grow up to 50 cm tall, and have emergent leaves borne on petioles that are not swollen or inflated like the spongy leaf stalks of water hyacinth, which aid in buoyancy. Spongeplant produces stolons which bear gametes.
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This species reaches an incredible height of , with a smooth, grayish trunk up to in diameter. The large, spherical crown typically contains up to 30 ascending, spreading to drooping leaves, with the long and wide slightly wavy blades held on petioles or more in length which are abundantly covered along both edges at the base in medium tan fibers. The leaves, glossy green above and below, are divided to 2/5 into many pendulous-tipped segments, with the abaxial surface incompletely covered with scattered fuzz. The inflorescences are composed of 1-4 panicles, shorter than or equalling the petioles in length.
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Malacothrix californica is a species of flowering plant in the aster family known by the common name California desertdandelion. It is native to California, the western margin of Arizona and Baja California, where it may be found especially in the South Coast, Transverse and Peninsular Ranges and the western Mojave Desert. Involucres (8–)10–15 × 5–6 mm. Phyllaries usually 20–26+ in 2-3+ series, (midstripes often reddish) lanceolate to lance-linear or subulate, unequal, hyaline margins 0.1–0.5 mm wide, abaxial faces (of outermost, at least) shaggily piloso-hirsute to arachnose (at least proximally).
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In fact, this order of xylem maturation characterizes the actinosteles (protosteles with ribbed primary xylems) of Sphenophyllum (Cichan, 1985), Eviostachya (Leclercq, 1957; Wang, 1993), Hamatophyton (Li et al., 1995), Rotafolia (this paper) and sphenophyllalean strobilar axes (Levittan & Barghoorn, 1948; Stewart & Rothwell, 1993: 194). However, the fertile unit of the strobilus of Rotafolia has an elongate- cuneate bract with a distal segment and lateral elongate segments, as well as numerous elongate abaxial sporangia pendulous at the base of the bract, which are distinct characteristics from other members of the Sphenophyllales. Thus, considering classification at the family level, Rotafolia is now left as incertae sedis.
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It is distinguished from other Calamus species by having petioles less than 3cm, the lowest pair of leaflets are often reflexed across the stem, and almost naked on faces, while the newly emerged leaflets have abaxial weak whitish indumentum. As well, the female partial inflorescences are short and stiffly curved. The conservation status of the species is regarded as unknown, but there are strong concerns of the population in Laos as the species occupies a habitat especially vulnerable to clearance because of agricultural intensification. There may be populations at Tonle Sap, Cambodia, which would ensure a secure population, but it not there is moderate concern.
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The economically important host of Albugo occidentalis is spinach (Spinacia oleracea); although the oomycete has also been reported to affect plants of the genus Chenopodium, the genus including the crop plant quinoa. This pathogen causes white rust or white blister of spinach. It is unrelated to the basidiomycete rusts biologically, but appears somewhat similar on the surface of the leaf, sometimes causing the plant to form white or yellow blister-like pustules on leaves. The early stage, a milder chlorosis, is found on the on abaxial face, but if the white rust is allowed to thrive, it can blister and be visible on the adaxial surface as well.
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Begonia gironellae is an endemic species of Begonia discovered in Tanabag, Puerto Princesa, in northern Palawan, Philippines. The species resembled Begonia cleopatrae, in that both species have widely ovate, variegated leaves, and fleshy hairs fused into a ring at the base of the leaf petiole. However, Begonia gironellae differed from B. cleopatrae due to its rosette habit with rhizome shorter to 5 cm long, with very congested internodes, widely triangular stipules, differently-sized lamina and bracts, and capsule with wider abaxial wing. Additionally, B. gironellae is a lowland species occurring in broadleaved seaside forests, while B. cleopatrae grows on hill forest at ca. 400m.
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The pedicel is 1 cm, green; the perianth has a short green tube, 5 mm, much shorter than the tepal segments, spreading in six white tepals, 15 mm long and 2.5 mm wide, linear-lanceolate, a bit broadened below the apex, gradually attenuate (narrowing) towards the base, subequal (nearly equal), keeled green on the abaxial surface, keel formed by 3 closely spaced veins. The stamens are biseriate, free, inserted at the throat, 3 equaling the tepals, 3 shorter; filaments filiform; anthers dorsifixed (attached to the filaments at their middle), oblong, versatile, yellow; style white, filiform, and terete. Stigma captitate, obscurely 3-lobed. Ovary with 3 locules; ovules 5-6 per locule.
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Each fertile unit comprises a bract and a cluster of five axillary peltate sporangiophores bearing several concentric cycles of sporangia. Two sporangiophores are distally, two are proximally directed and one is at 90° to the strobilar axis. The strobili of Rotafolia differ from those of Bowmanites, Sphenostrobus and Peltastrobus in that the bracts are independent and bear distal and lateral elongate segments; multiple abaxial sporangia are attached to the base of the bracts at the same level. Recorded in the Upper Devonian, Eviostachya hoegii (Leclercq, 1957; Wang, 1993) is a sphenopsid that has whorls of divided vegetative leaves and opposite strobilar axes at nodes.
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The leaf has a different texture on each side; the abaxial (top) side of the leaf is hairy while the adaxial (bottom) side is smooth. The leaf's blade has an inversely-ovate to oblong-round shape and is approximately 4 to 7 centimeters long and approximately 1 millimeter wide. The upper sides of the leaves have a hairy, shaggy texture with glandular hairs, while the undersides of the leaves have thread-like trichomes that measure 2 to 2.5 millimeters long and are of golden color. The stipules are rectangular and have membranous schlitzblättrig with the slit measuring up to 7 millimeters long and about 6 millimeters wide.
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The salt glands of mangroves such as Acanthus, Aegiceras, Aegialitis and Avicennia are a distinctive multicellular trichome, a glandular hair found on the upper leaf surface and much more densely in the abaxial indumentum. On the upper leaf surface they are sunken in shallow pits, and on the lower surface they occur scattered among long nonglandular hairs composed of three or four cells. Development of the glands resembles that of the nonglandular hairs until the three-celled stage, when the short middle stalk cell appears. The salt gland continues to develop to produce two to four vacuolated cells at the level of the epidermis, the stalk cell with an almost completely cutinized wall, and at least eight terminal cells.
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Ornithogalum species are perennial bulbous geophytes with basal leaves. Sensu lato, the genus has the characteristics of the tribe Ornithogaleae as a whole, since the tribe is monotypic in that sense. Sensu stricto, the genus is characterised by long linear to oblong-lanceolate (lance-shaped) leaves, sometimes with a white longitudinal band on the adaxial (upper) side, an inflorescence that is corymbose or pseudocorymbose, tepals that are white with a longitudinal green band only visible on the abaxial (lower) side, a capsule that is obovate or oblong, and truncate with six noticeable ribs in section and seeds that are globose with a prominently reticulate (net-like pattern) testa. The bulbs are ovoid with free or concrescent scales.
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Very similar to, and sometimes mistaken for, Epacris serpyllifolia, Archeria comberi has a number of key characteristics that enable its identification, especially the distinct pink, tubular flowers, with pink and yellow stigma and stamen, and fused sepals. These flowers are situated on a short stalk close to the end of each flowering branch. When not in flower, this species is characterised by: woody branches and branchlets with scattered hairs, rounded woody capsules with a star like opening during dispersal, small(~ 3–4 mm), waxy, round with a pointed tip, green and often red leaves arranged in whorls around the stem. With usually 3 faint almost parallel veins, each leaf generally has a light green abaxial surface, predominantly green, sometimes red adaxial surface and a red edge.
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Tibouchina araguaiensis PJF Guim is a shrub that has been found only in Araguaia National Park in the state of Tocantins, Brazil and was described in 2014. It grows in the transitional area between forest and meadows at 200 metres in sandy soil. This species is very similar to Tibouchina papyrus Distinguishing characters include the triangular hypanthial scales which cover the entire hypanthium, and the abaxial leaf surface which is only sparsely covered by ciliate scales; in T. papyrus, the prominent scales cover the entire lower leaf surface. These species also differ in their distribution; Tibouchina araguaiensis is found on the flat topography of Araguaia National Park, while T. papyrus is endemic to the higher elevation campos rupestres in southeast Tocantins and western Goiás.
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In these examples, elongate projections suggest lateral segments on the other side of the blade, which are shown by dotted lines in Figure 42B, C. They were folded and then pressed close to the upper surface of the bract blade. In oblique abaxial view, lateral elongate segments are observed on either one side (Fig. 42D, E) or two lateral sides (Figs 35, 36, white arrows) of the bract blade. In lateral view, the distal segment of the bract is sometimes visible (Figs 24, black arrows, 28, white arrows, 41, arrows, 42F, arrow); in one example, a distal segment is up to 8.0 mm long and dichotomous (Fig. 26, arrow); lateral segments slightly reflex towards the strobilar axis (Figs 28, 35, 36, 39).
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Pherosphaera hookeriana is a densely-branched erect shrub or small tree growing to heights of 5 meters, branches are often small and rigid with leaves arranged spirally and fully appressed to the stem. Individual leaves can measure up to 1.5 millimetres (mm) long, and 1 mm wide, leaves are thick, blunt and concave with a rounded keel. Male flowers in compressed, terminal globular cones, ranging from 1–5 mm in diameter, with 8 to 15 fertile scales, each scale has two pollen sacs on the abaxial surface. Female flowers occur in cones on short branches that usually droop (hence the old common name) flowers are globular ranging from 2–4 mm long and have 3-8 fertile scales, with a single ovule on the upper surface of each scale.
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They are herbaceous procumbent glabrous plants. They are mostly blackened when they are dry. Their stems are 5–40 cm in length and they have 4-alate leaves. Ovate leaves 7–25 mm in length and 3–16 mm wide, with a crenate edge; petiolate. Solitary axillary flowers, pedicles 8-20 (-26) mm in length, basally bibracteolate; 5-lobed calyx, with unequal lobes, more or less free to the base, imbricate, the adaxial lobe widely lanceate to ovate, 5-9.5 mm long and 3–6 mm wide, slightly accrescent, the 2 middle lobes longer and overlapping, the 2 abaxial lobes nearly the same size as the adaxial and overlapping the middle lobes; 5-lobed corolla, 7–8 mm long, yellow with purple at the throat, bearded at the mouth; 4 fertile stamens.
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Inflorescence (as above) The authors describe the plants as having solitary stems (but sometimes with basal shoots), maximum: 2 m tall and 40 mm in diameter. There are typically 18 leaves; leaf sheaths are not known in their entirety, they are extended above the petioles into "ocreas" (extensions of the leaf sheath), which are 200 mm long. Petioles are 1.36 m long, 4 mm wide at the apices, with widely spaced, recurved, thorns. Leaf blades are approximately 800 mm wide, split into 12 segments, these with straight sides; middle segment not wider than the others (and not split with no petiolules) 465 mm long, 65 mm wide at the apex; indentations leading to adaxial folds 5 mm deep, those leading to abaxial folds 3 mm deep, indentations deeper on lateral segments.
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Woody shrubs to 2 m tall. Stems erect but arching towards apices, many of these becoming spiny, older portions glabrous, becoming pubescent towards younger portions of stem, trichomes simple, < 0.25 mm, the internodes 4-35 mm long. Spines 3-8 cm, 0.2-0.3 mm in diameter at base. Leaves borne in clusters on very short shoots (these < 1 mm long), subtended by dense protrusions of trichomes, on short petioles to 5 mm long, these pubescent with short eglandular trichomes or glabrous, the blades simple, alternate, narrowly obelliptic to narrowly elliptic, 20-50 × 3-10 mm, (2-)4.7 to 7.5 times longer than wide, the bases attenuate, the apices broadly acute to obtuse, the margins entire, both surfaces covered by glandular trichomes (these seeming to result in black spots on pressed specimens) with occasional sparse simple trichomes along midrib of abaxial surface.
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Its strongly pouched ultimate segments mean it can be confused only with G. dicarpa. From that species, G. alpina can be distinguished by: the absence of stellate scales with patent branches on the β costae; the strongly convex adaxial surface of the ultimate segments; only 0–1 (rarely 2) pseudodichotomous forks in the pinnae (excluding growth from pinna buds); the absence of accessory leaflets around the rachis bud; and pinna buds that usually extend, often more than once. In contrast, G. dicarpa has: stellate scales with patent branches (curled in Chatham Islands’ plants) on the abaxial and/or adaxial surfaces of the β costae; complanate or weakly convex adaxial surface of the ultimate segments; 1–4 (rarely 0 or 5) pseudodichotomous forks in the pinnae (excluding growth from pinna buds); usually accessory leaflets around the rachis bud; and pinna buds that extend only occasionally and rarely more than once.
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The four petals are mostly creamy white, oblong-ovate, consist of a more yellowish straight and narrow claw and a wide plate. The forward directed lower (abaxial) pair is long and 2½–3 mm (0.10-0.12 in) wide the upper ⅔ deeply incised to create nine or ten finger-like lobes, often themselves ones or even twice split into two lobes (also described as a lacerate margin). The upper (adaxial) pair is long and 3½–5 mm (0.12-0.20 in) wide, less deeply incised with four to six finger-like lobes. The tube-shaped nectaries are yellow, but become purple when drying and are 1-5½ mm (0.02–0.12 in) long. There are six to fifteen stamens that reach beyond the petals, consist of purple 1–1⅓ cm (0.4-0.5 in) filaments topped by purple, 1–1½ mm (0.04–0.06 in) long anthers, which do not coil when the pollen is released.
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