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1 Base of achene without hypogynium (a circular, angular, lobed, or tuberculate disk differing in texture and structure from the achene body), the achene base constricted, pitted, and/or ribbed, but appearing as a continuation of the achene body. | |
2 Inflorescence of 1 terminal and 1-3 axillary spikes or panicles, each spike or panicle subtended by a foliaceous bract; [subgenus Hypoporum, section Hypoporum] | |
2 Inflorescence terminal only; if glomerules spike-like along an axis, then only the lowest with a (or no) bract. | |
3 Inflorescence of 2-9 sessile clusters along an axis up to 13 cm long, the individual spikelets 2-5 mm long; bracts (at least above proximal cluster) setaceous; [subgenus Hypoporum, section Hypoporum]. | |
4 Plants annual with fibrous roots; leaf blades glabrous, 0.5-2 mm wide; bract and scale margins eciliate; spikelets 2-3 (-4) mm long; achenes reticulate-papillose to reticulate-verrucose | |
3 Inflorescence of a single cluster, the individual spikelets 4-10 mm long; bracts foliaceous; [subgenus Trachylomia, section Trachylomia]. | |
7 Hypogynium with 8 or 9 tubercles, the tubercle surface minutely papillate; [subgenus Trachylomia, section Trachylomia] | |
7 Hypogynium not divided into tubercles, either smooth and angled/lobed, or minutely papillate and continuous (not lobed). | |
9 Leaves 7-11 mm wide; achenes 1-2 mm long; hypogynium margin moderately to densely white-ciliate or ciliolate | |
11 Plants perennial, rhizomatous; culms scabrous only on angles; larger leaves 3-10 mm wide, glabrous; achenes ± 2 mm long, body purplish to black, summit mucronate; hypogynium dark brown (margins paler), the 3 lobes flat, broad, and rounded apically | |
11 Plants annual, without rhizomes; culms strongly retrorsely-scabrous; larger leaves 10-25 mm wide, sparsely pubescent; achenes 3.4-3.8 mm long, body greenish to whitish, sometimes mottled gray, summit rounded; hypogynium whitish to pale brown, bluntly 3-angled; [subgenus Scleria, section Margeleia] | |
10 Hypogynium not 3-angled or 3-lobed, surface minutely papillate; [subgenus Trachylomia, section Trachylomia]. | |
13 Plants cespitose to short-rhizomatous; sheaths brown or stramineous to reddish, glabrous to glabrate on the ventral surface except for a pubescent and usually thickened summit; inflorescences terminal and lateral; achenes 2.0-3.3 mm long, (1.12-) avg. 1.25 (-1.38× as long as wide; hypogynium surface with laterally and apically rounded papillae; [of wet to mesic pinelands] | |
13 Plants long-rhizomatous or cespitose; sheaths purple to reddish, the ventral surface uniformly pubescent; inflorescences terminal only or terminal and lateral; achenes 2.5-4.0 mm long, (1.35-) avg. 1.45 (-1.54)× as long as wide; hypogynium surface with rounded or flattened papillae; habitats various. | |
14 Plants usually cespitose; inflorescence terminal and lateral (a few culms in a clump can be terminal only); hypogynium surface with laterally flattened and apically triangular-acute to acuminate papillae, often resembling shards of glass or porcelain; [of coastal hammocks, oak woods near saltwater, and blackwater swamps] | |
14 Plants usually long-rhizomatous; inflorescence terminal only; hypogynium surface with laterally and apically rounded papillae; [mostly of dry to dry-mesic pinelands and barrens] | |
6 Achene reticulate or papillose, rarely smooth (most often from apparent abortion or abnormal development); hypogynium with 3 tongue-shaped lobes, or 3 or 6 tubercles. | |
15 Hypogynium of 3 tongue-shaped lobes appressed to the underside of the achene (appearing nearly bract-like); achene reticulate, the pits generally squarish or rectangular and arranged regularly in rows, rarely smooth (apparently by abortion or abnormal development); [subgenus Scleria, section Foveolidia]. | |
15 Hypogynium with 3 or 6 tubercles; achene papillose, sometimes reticulate (if so, the pits generally variable in shape and not forming regular rows), or rarely smooth; [subgenus Trachylomia, section Trachylomia]. | |
17 Leaves 1-2.5 mm wide; hypogynium with 6 tubercles; achene 1.0-2.5 mm long, the body papillate or roughened-reticulate. | |
17 Leaves 1-7 mm wide; hypogynium with 3 (sometimes deeply lobed) tubercles, achene papillate or roughened-reticulate, 2.0-3.5 mm long; or hypogynium tubercles 6 and achene epapillate and smoothish, 2.5-3.4 mm long. | |
19 Achene body smoothish with broad low rises, epapillate except for a few retrorse pappi at the very base, sometimes a faint transverse ridge near the base; achene including hypogynium 2.5- 3.2 (-3.4) mm long, 2.3-2.7 mm wide; hypogynium disk 1.4-1.8 (-2.1) mm wide, 0.1-0.2 (-0.3) mm thick; tubercles 6 (rarely 3 deeply lobed); longer cilia on terminal inflorescence primary bract 1.1-2.2 mm; longer pistillate scale keel cilia 0.5-1.0 mm; leaf blades (2.5-) 3-7 mm wide, ciliate with stiff hairs on margins and primary veins, rarely with a few stiff hairs between the veins, lacking fine puberulent hairs | |
19 Achene body papillose throughout, often transversely ridge or reticulate (rarely papillae absent in reticulate achenes); achene including hypogynium 2.0-3.3 (-3.5) mm long, 1.7-2.4 (-2.6) mm wide; hypogynium disk (0.6-) 0.8-1.4 (-1.6) mm wide, 0.1-0.4 (-0.5) mm thick; tubercles 3, entire to deeply lobed; longer cilia on terminal inflorescence primary bract 0-1.1 (-1.3) mm; longer pistillate scale keel cilia 0-0.5 mm; leaf blades 1-6 mm wide, glabrous to ciliate on margins and primary veins to puberulent with fine hairs over entire surface, especially adaxially. | |
20 Leaf blades (2.5-) 3-6 mm wide, at least some adaxial surfaces puberulent throughout, often ciliate with stiff hairs on margins and primary veins; terminal inflorescence primary bract 1.2-4.1 mm wide at widest point, its longer cilia 0.7-1.1 (-1.3) mm long; hypogynium disk 1.1-1.4 (-1.6) mm wide, (0.1-) 0.2-0.4 (-0.5) mm thick | |
20 Leaf blades 1-3 (-3.5) mm wide, adaxial surface glabrous and eciliate, or glabrous and ciliate on margins, or puberulent and ciliate; terminal inflorescence primary bract 0.4-2.2 mm wide at widest point, its longer cilia (0-) 0.1-0.7 (-0.9) mm long; hypogynium disk (0.6-) 0.8-1.3 (-1.5) mm wide, 0.1-0.2 (-0.3) mm thick. | |
21 Plants ciliate (sometimes sparsely so) on leaf blade margins (also sometimes on primary nerves), culm angles, and margins of terminal inflorescence primary bract, the surfaces between margins or angles glabrous to puberulent | |
21 Plants glabrous on leaf blade and culm surfaces, angles, and margins (terminal inflorescence primary bract often ciliate or scabrous on margins, rarely smooth); sheaths, especially lowest, usually puberulent |