retrorse


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retrorse

[ri′trȯrs]
(biology)
Bent downward or backward.
References in periodicals archive ?
Aedeagus as in generic description, with shaft curved ventrad furnished with retrorse small spines, periandrum obtusely bent caudally at apical third; a small slightly sclerotized plate contacts the periandrum with the ventral margin of the anal segment; connective stout, long, length/wide 10:1 (Fig.
24) with 23-26 ([male] [female]) strongly retrorse teeth, most with arcuate margins; movable finger (Fig.
Stems 1.5-4.5 dm, erect, usually divaricately branched above, strigillose with retrorse or rarely spreading trichomes.
Head narrow; perifacial rim narrow and terminating in a retrorse spine; rostral and nasal spines absent (Fig.
2.5 cm long, 4.5-5 cm in diameter (including floral bracts), floral bracts narrowly ovate, apex acuminate, distinctly canaliculate, navicular, ecarinate, strongly recurved, exceeding the sepals, yellowish-green to orange (when fully exposed), thin in texture, inconspicuously and sparsely white-lepidote near the base to glabrous, glabrous toward the apex, nerved abaxially, 25-35 x 11-15 mm, densely spinose, spines narrowly triangular, the basal ones retrorse the median to apical ones antrorse, uncinate, greenish except for the pale castaneous apex, 0.5-1.5 mm long, 0.5-1 mm apart.
Articular with retrorse condyle on posterodorsal facet serving as insertion for ligament from quadrate.
Leaves erect, curved at apex, acute to somewhat apiculated, lustrous green above, somewhat dull below, 6070 cm long, 6,4-7 cm wide, leaf sheath 11,5-12 cm long, glabrous, margins with dark antrorse, straight or retrorse thorns to 5 mm long, leaf apex with a reflexed mucro.
Perigynia with a conspicuous exserted rachilla tipped by a retrorse, inrolled scale (i.e., an uncus or hook) II.
1.5 cm long, abaxially completely covered by a coarse layer of white trichomes, adaxially sparsely and inconspicuously white lepidote except for the densely white lepidote apex, coarsely spinulose, spines sub-triangular, uncinate, blackish, 3-5 mm long, 8-20 mm apart, the basal ones prevailing antrorse, the upper ones prevailing retrorse. Scape stout, erect, ca.
Leaves 3-9; blades 4-16(-23) cm long, (0.7-)1-3.4 mm wide, flattish or channelled (at least proximally), glabrous, margins with unbranched and 2-branched prickle hairs, the unbranched ones antrorse or retrorse; inner band of leaf sheaths white-hyaline or pale brown, glabrous, the apex slightly concave; ligules 0.5-1.5 mm long, more or less rounded.
0.5 mm wide at base, 2-3 mm apart from each other, acicular, spreading to slightly retrorse, reddish-castaneous, glabrous.
3 x 3.3 cm, densely and minutely spinulose at apex, greenish-white, glabrous toward base, densely and coarsely white-lepidote and strongly corrugate at apex; blades narrowly triangular, apex slenderly acuminate-caudate, 15-18 x 2-2.3 cm, not narrowed toward base, strongly coriaceous but without any thicker central zone, strongly canaliculate, green, densely and coarsely white-lepidote abaxially with trichomes obscuring leaf color, adaxially densely white-lepidote toward base and glabrous toward apex, margins straight, subdensely spinulose; spines 1-1.5 mm long, 3-8 mm apart, the basal ones subspreading to slightly retrorse, the upper ones slightly antrorse-uncinate.