trigonous


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trigonous

[′trig·ə·nəs]
(biology)
Having three corners.
Having a triangular cross section.
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1-3 l (a), 2-3 Kyllinga 1-3 2 Kyllingiella 1-3 3 Lipocarpha 1-3 2-3 Oxycaryum 3 2 Pycreus 1-3 2 Queenslandiella 2 2 Remirea 3 3 Sphaerocyperus 3 3 Volkiella 2 3 Ficinia Clade Dracoscirpoides 3 3 Erioscirpus 2 3 Ficinia 3 3, 2-1 (a) Hellmuthia 3 3 Isolepis 1-3 2-3 Scirpoides 2-3 3 Ovary shape and Style base Taxon orientation persistence Cyperus Clade Alinula Trigonous Persistent Androtrichum Trigonous Persistent Ascolepis Trigonous/Dimerous- Deciduous dorsiventrally compressed Courtoisina Trigonous Persistent Cyperus s.s.
Stems 20-90 (-125) cm tall, 1-3 mm wide, trigonous to subterete, often somewhat compressed, glabrous or lightly pubescent.
Plants perennial, densely cespitose; fertile culms 50-110 cm tall, sharply trigonous, smooth, with glabrous, brown basal sheaths.
Species of subgenus Carex display the greatest variation in achene shape of all the major Carex groups, ranging from biconvex to trigonous, and from ovate to obovate, rhomboid or orbicular, with one to two lateral flexa (abrupt changes in curvature).
Column erect, slightly arcuate, trigonous, apiculate, 8(9) mm long, 4-5 mm wide at apex, base and middle whitened to pinkish, towards apex purple, stigmatic surface green; column foot (2)3(4) mm long, yellowish.
Plants in dense clumps with many culms; culms 24-50 cm tall, 0.3-1 mm wide, erect, obtusely trigonous to compressed-trigonous (about 0.2 mm thick), coarsely ribbed, smooth or almost so.
Fertile culms 4-30(-45) cm tall, erect or slightly curved, more or less trigonous (especially distally), smooth but sometimes scaberulent beneath the inflorescence, with glabrous, brownish basal sheaths.
4 mm wide at apex, trigonous; epigynous tube lacking; placentation apical; ovules obtuse, green.
Cypselae trigonous, truncate, glabrescent; pappus of rigid, scabrid bristles, plumose to scabrid at the apex.
Styles trifid or some bifid in the same spikelet; achenes plano-convex, slightly trigonous or biconvex, minutely reticulate 2 2.
7 mm long, sublinear, base acute and apex acute and apiculate, dorsifixed at the middle, the antesepalous ones slightly exceeding the antepetalous ones; pollen biporate, broadly oblong-elliptic, pores large, exine reticulate, lumina polygonal, muri narrowed; stigma conduplicate-spiral, ellipsoid, white, lobes with densely crenulate-papillose margins; ovary clavate, trigonous, white, glabrous, ca.
5 mm long, whitish, margins long fimbriate-papilose, papillae conspicuous; ovary subclavate, subterete to nearly trigonous, free and not fused to other ovaries, whitish, ca.