Rhynchospora fascicularis |
Rhynchospora nivea |
|
---|---|---|
fascicled beaksedge |
showy whitetop |
|
Habit | Plants perennial, cespitose, 100–150 cm; rhizomes absent. | Plants perennial, cespitose, 10–40 cm, wiry; rhizomes absent. |
Culms | erect to excurvedascending, narrowly linear to ± filiform, terete to obscurely trigonous, leafy, densely so toward base, stiff to rather lax. |
erect to spreading-ascending, leafybased, trigonous or compressed, ribbed. |
Leaves | overtopped by culm; blades linear, ascending, proximally flat, 1–4 mm wide, apex trigonous, subulate, tapering gradually. |
exceeded by scape; blades narrowly linear to filiform, 0.2–2 mm wide, apex tapering, trigonous. |
Inflorescences | spikelet clusters 1–3(–4), proximal mostly widely spaced, dense, broadly turbinate to hemispheric, to 2 cm broad; leafy bracts subulate, exceeding proximal spikelets, slightly or not exceeding most distal clusters. |
terminal, solitary, headlike, dense, white, leafyinvolucrate, hemispheric to globose, 0.5–1.5 cm wide; involucral bracts (0–)1–4, ascending to recurved, green, (0.7–)2–5(–6) cm × 0.2–2 mm. |
Spikelets | redbrown, narrowly ovoid, (3–)3.5–5 mm, apex acute; fertile scales ovate, 3–3.5(–4) mm, apex acute, mostly with cusp or mucro 0.5–1 mm. |
white, ovoid, 5–7 mm; fertile scales several, boat-shaped, 2.5–3.5 mm, keel curved, not sharp. |
Flowers | bristles 5–6, from rudimentary to reaching tubercle tip, or (rarely) beyond, antrorsely barbellate. |
perianth absent. |
Fruits | 1–3 per spikelet, (1.5–)2–2.2(–2.5) mm; body dark brown with pale center, lenticular, broadly ellipsoid to ± orbicular, (1.3–)1.5–1.7(–1.9) × 1–1.5 mm, margins pale, narrow or narrowly rounded, flowing to tubercle; surfaces dull, minutely longitudinally striate; tubercle compressed, triangular to triangularsubulate, 0.5–0.7(–0.9) mm. |
0.8–1 mm; body yellow to near black, broadly pyriform-obovoid, tumidly lenticular, 0.5–0.8 × 0.5–0.8 mm, margin narrow, flowing into tubercle; surfaces transversely sharply wavyrugose, ridges bordered by rows of fine, linear, vertical lattices; tubercle depressedtriangular, lunate-based, shortbeaked 0.2(–0.3) mm, gray-crustaceous. |
Rhynchospora fascicularis |
Rhynchospora nivea |
|
Phenology | Fruiting late spring–fall or all year (south). | Fruiting spring–fall. |
Habitat | Sands and peats of interdunal swales, depressions in savannas, open flatwoods, and seep-bog edges | Low, open, moist to wet, basic substrates of fens, meadows, seeps, and shores, limestone districts |
Elevation | 0–100 m (0–300 ft) | 0–500 m (0–1600 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX; VA; Central America; Bermuda
|
OK; TX |
Discussion | In her revision, S. Gale (1944) treated var. distans as the more slender version of the species, one with a smaller inflorescence, more distinctly margined fruit body, and consistently elongate perianth bristles. All those character states appear to vary independently over the total range of the species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Rhynchospora nivea, of the “Dichromena” of North America, is the smallest fruited and most slender and has the fewest and shortest involucral bracts (in some plants the bract is entirely absent). Involucral bracts of R. nivea are almost entirely green. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 239. | FNA vol. 23, p. 216. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Schoenus fascicularis, Dichromena distans, Phaeocephalum fasciculare, Phaeocephalum distans, R. distans, R. distans var. fascicularis, R. dommucensis, R. fascicularis var. distans, Schoenus distans | Dichromena diphylla, Dichromena nivea |
Name authority | (Michaux) Vahl: Enum. Pl. 2: 234. (1805) | Boeckeler: Linnaea 37: 527. (1872) |
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