Synsets for "acroscopic"

Synset: acroscopic.a.01

Synonyms: acroscopic

Part of Speech: ADJECTIVE

Definition: facing or on the side toward the apex


Lemmas: acroscopic



Antonyms: basiscopic


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Asplenium bradleyi "Asplenium bradleyi" is a small fern with dark green, pinnate-pinnatifid to bipinnate fronds. These form evergreen, perennial tufts. Notable characteristics are the dark stem, whose color extends well up the axis of the leaf blade, a deeply cut acroscopic lobe or pinnule at the base of each pinna, and toothed pinna edges. However, some of these characteristics are variable, and may not be observed in all individuals of "A. bradleyi". Some specimens have rounded, rather than toothed edges and others lack dark coloration throughout most of the stem. The fronds are monomorphic, the sterile and fertile fronds appearing the same size and shape.
Dryopteris macropholis The pinnae are opposite to subopposite, (11–)13–20 on a side, spreading, ovate-oblong to linear-oblong, apex acuminate, lowermost pinnae the largest, 20–33 × 11–19 cm, with 11–16 pairs of pinnules, slightly inequilateral, basiscopic basal pinnules 7–10.5 cm long, acroscopic basal pinnules shorter, 4–8.5 cm long, lowermost pinnules usually the largest, distal pinnae stalked 3–6 mm becoming sessile, apices pinnatifid; largest ultimate pinnules 12–19 × 4–8 mm, spaced 5–10 mm distant, obtuse to truncate at apices, margins crenate or cut ca. 1/4 –2/3 toward costule, adaxially glabrous, abaxially glabrous except for scattered small, spreading, brown linear scales on rachises; veins forking 1–2 times, scarcely visible to visible on both surfaces, depressed adaxially and prominulous abaxially; each fertile pinnule usually with 1–4 pairs of inframedial sori. Sori with indusia 0.4–0.6 mm in diameter, brown, thick, glabrous. Spores dark brown.
Asplenium bradleyi Among fertile species, "A. bradleyi" most closely resembles its parent species "A. montanum". Several characteristics exit to distinguish them: the pinnae of "A. bradleyi" are toothed and less deeply lobed or cut than "A. montanum" (where the pinnae are often fully cut to pinnules), the dark color of the stipe extends into the rachis, the upper pinnae lack stems, and the overall shape of the leaf blade is parallel-sided, rather than lance-shaped. "A. bradleyi" also shows some resemblance to black spleenwort ("A. adiantum-nigrum") (although their ranges do not overlap). The latter may be identified by its distinctly triangular-shaped leaf blade, more deeply cut leaves (the pinnules of its basal pinnae are lobed), and enlarged basiscopic, rather than acroscopic, pinnules.
Asplenium bradleyi "Asplenium bradleyi" is similar to two hybrid species of which it is a parent, Graves' spleenwort ("A. × gravesii"), a hybrid with "A. pinnatifidum", and Wherry's spleenwort ("A. × wherryi"), a backcross with "A. montanum". In "A. × gravesii", the dark color of the stipe ends at the base of the leaf blade, the pinnae are more shallowly lobed and the enlargement of acroscopic lobes or pinnules is less distinct, and the apical portion of the blade forms a long, tapering tip with slight lobes (as in "A. pinnatifidum"), rather than being cut into pinnae. In addition to the general reduction of the toothiness of "A. bradleyi", "A. × gravesii" also shows faint winging along the stipe. Likewise, in "A. × wherryi", the dark color of the stipe again ends at the base of the leaf blade, the overall shape of the blade tends to be more distinctly lance-shaped, and the fronds are somewhat more deeply cut than "A. bradleyi", progressing from bipinnate in the lower half to pinnate-pinnatifid and finally pinnate at the apex. Finally, the diploid hybrid "A. montanum × platyneuron", from which "A. bradleyi" arose by chromosome doubling, is essentially identical in appearance to "A. bradleyi". On close examination, its spores are found to be abortive, and the sori are smaller and not do not become fused with each other as they grow, as they do in fertile "A. bradleyi".
Asplenium bradleyi The overall shape of the blade ranges from oblong (tapering at the ends but about the same width throughout) to lanceolate (slightly wider a short distance above the base, tapering to a point at the apex). It is squared off at the base and tapers at the tip. The blade ranges from long, rarely to , and in width, and may be thin or somewhat thick. The blade is cut into 5 to 15 pairs of pinnae (possibly as low as 3 or as high as 20 in unusual specimens), which are themselves deeply lobed or further subdivided into pinnules. The lower pinnae are stalked, while the upper pinnae are not. They are variable in shape, tending to have a squared-off or very broadly curved base, and are typically widest at or near the base. The acroscopic lobe or pinnule nearest the rachis (located on the apical side of each pinna) tends to be enlarged, and the pinnae are toothed. They vary from in length and at the middle of the frond.
Asplenium bradleyi While both Asa Gray and Eaton identified "A. bradleyi" as a hybrid intermediate between "A. montanum" and "A. platyneuron", the English botanist R. Morton Middleton proposed in 1892 that it was identical or closely related to "A. viride". This conclusion was based on the examination of forms growing in shade on the Cumberland Plateau which lacked color in the rachis, and was endorsed by contemporary Tennessee botanists such as Augustin Gattinger and Kirby Smith. This was rebutted in 1893 by Amos A. Heller, who pointed out that most collections of "A. bradleyi" had a dark stipe and that it possessed an auricle (the acroscopic pinnule) which "A. viride" lacked. Instead, Heller perceived in some of his specimens from the lower Susquehanna River affinities to "A. montanum" and "A. pinnatifidum". Middleton, nevertheless, continued to maintain his theory of an affinity with "A. viride", and speculated that "A. bradleyi" was not a hybrid, but an "intermediate" between "A. viride" and lanceolate spleenwort ("A. obovatum" ssp. "lanceolatum").
Adiantum viridimontanum The ultimate segments of the divided blade (the apparent "pinnules") are borne on short, dark stalks of 0.6 to 1.5 mm, with the dark color often spreading into the base of each segment. They are long and obliquely triangular, the basiscopic margin forming the hypotenuse. The tip of the segments is typically acute, but entire (not pointed). They measure from 9.5 to 22.5 mm in length and 4.2 to 7.5 mm in breadth, the average length being about 2.5 times the breadth. Their tissue is herbaceous (firmly leafy) to chartaceous (parchment-like) in texture, and bright green to bluish-green in color. As in other members of "Adiantum", the glabrous leaves shed water when young. Under shady conditions, the ultimate segments lie within the plane of the blade, but tend to twist out of the plane when grown in the sun. The acroscopic margins of these segments are lobed, with narrow (less than 1.0 mm) incisions lying between lobes. In fertile segments, these lobes are recurved to form false indusia beneath the leaf. These are transversely oblong, from 2 to 5 mm in length and from 0.6 to 1.4 mm in width.