Scirpus pallidus
Scirpus atrocinctus
cloaked bulrush, pale bulrush
black-girdle bulrush, black-girdle woolsedge, common woolly sedge, scirpe à ceinture noire, wool-grass
fertile ones upright or nearly so;
nodes without axillary bulblets.
fertile ones upright or nearly so;
nodes without axillary bulblets.
5–10 per culm;
sheaths of proximal leaves green or whitish;
proximal sheaths and blades with septa many, conspicuous or not;
blades 20–55 cm × 8–16 mm.
4–7 per culm;
sheaths of proximal leaves brown;
proximal sheaths and blades with septa few to many, conspicuous or inconspicuous;
blades 25–63 cm × 3–6 mm.
terminal, rarely also with 1 lateral inflorescence from distal leaf axil;
rays ascending or divergent (commonly both in same inflorescence), smooth throughout or scabrous at distal end, rays without axillary bulblets;
bases of involucral bracts green or margins brown, not glutinous.
terminal;
rays ascending or sometimes spreading, scabrous throughout or main branches smooth proximally, rays rarely with axillary bulblets;
bases of involucral bracts usually blackish, not glutinous.
aggregated in a few dense clusters of 12–130 (largest cluster with 40–50+), spikelets sessile, narrowly ovoid, 4–5 × 1.8–2.3 mm;
scales black or brownish black with pale midribs, elliptic to ovate, 1.6–2.8 mm, ending in terete or flat awn 0.4–0.6(–1.2) mm.
in open cymes, central spikelet of each cyme sessile, others usually pedicellate, spikelets ovoid or ellipsoid, 4–7 × 2–2.7 mm;
scales usually blackish, at least distally, oblong-ovate or oblong-elliptic, 1.3–1.8 mm, apex rounded or very weakly apiculate, apiculus (if present) to 0.05 mm.
perianth bristles persistent, 6, rather stout, straight or curved, longest bristles equaling achene, with retrorse, thin-walled, round-tipped teeth in distal 0.3–0.5, enclosed within scales;
styles 3-fid.
perianth bristles persistent, 6, slender, contorted, much longer than achene, smooth, projecting beyond scales, mature inflorescence appearing woolly;
styles 3-fid.
pale brown or almost white, oblong-elliptic to elliptic or obovate in outline, plumply trigonous or plano-convex, 0.8–1.2 × 0.4–0.6 mm.
whitish, elliptic or obovate in outline, plumply trigonous or plano-convex, 0.7– 0.9 × 0.4–0.5 mm.
= 56.
= 68.
Scirpus pallidus
Scirpus atrocinctus
Scirpus pallidus has been confused with S. atrovirens. The awned rather than mucronate scales distinguish S. pallidus from all similar species. The perianth bristles are similar to those of S. atrovirens; the scales of S. pallidus are almost always black, rather than brownish as in S. atrovirens. Inflorescences of S. pallidus consist of relatively few, large glomerules (the largest glomerule in the inflorescence usually has 50 or more spikelets). Some individuals of S. atrovirens may have glomerules with as many as 65 spikelets.
Scirpus pallidus occasionally hybridizes with S. atrovirens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Scirpus atrocinctus differs from S. pedicellatus by having more intense pigmentation in its inflorescence, both in the scales and the bases of the involucral bracts. Scales of S. atrocinctus are usually distinctly blackened, at least distally, and those of S. pedicellatus show either no black pigment at all or indistinct blackening beside the distal part of the midrib. Brown streaking throughout the scale is usually prominent in both species. The bases of the involucral bracts are almost always solid black in S. atrocinctus and reddish brown, brownish, or merely tinged or bordered with black in S. pedicellatus. The scales of S. pedicellatus also differ from those of S. atrocinctus in usually having a short mucro. All of these characteristics are variable. The two species are usually quite distinct when they grow close together, and they are not known to hybridize with each other (although each species hybridizes with S. cyperinus). It is often difficult to identify isolated herbarium specimens with confidence.
Scirpus atrocinctus often hybridizes with S. cyperinus and forms hybrid swarms. The type of S. pedicellatus forma viviparus F. G. Bernard appears to be S. atrocinctus × cyperinus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
OR
WA
Flora NW
KS Wildflowers
MN Wildflowers
MO Plants
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
Go Botany
IL Wildflowers
MI Flora
