Cyperus echinatus
Cyperus strigosus
globe flatsedge, teasel sedge
false flatsedge, false nutsedge, straw color cyperus, straw-color flatsedge, straw-colour flatsedge
basally cormlike, trigonous, (15–)30–100 cm × 0.5–3.5 mm, glabrous.
basally swollen and cormlike, trigonous, (1–)20–40(–90) cm × 1–6 mm, glabrous or few prickles subapically.
flat to V-shaped, 10–65 cm × 3–9 mm, adaxial surface, margins minutely scabridulous.
flat, (10–)20–40 cm × 1–4(–8) mm, margins and midribs glabrous or scabridulous.
spikes densely globose to globose-ovoid, 8–17 mm wide;
rays 3–12, 2–12 cm, scaberous adaxially especially distally;
rachis 4–8 mm;
bracts (3–)4–7, ascending at 30(–45)°, flat, 5–35 cm × 2–9 mm;
rachilla persistent, wings 0.5–0.7 mm wide.
spikes 1–4, loosely ovoid to oblong-cylindric; (6–)10–28(–50) × 10–40 mm;
rays sometimes absent, usually (1–)3–6(–8), 0.5–7(–25) cm;
if absent, inflorescence a congested head; 2d order rays sometimes present, 1–4(–9) cm;
rachis 8–18(–25) mm;
bracts (3–)5–7(–10), ascending at 30–45°, cross ribs sometimes conspicuous, (1–)10–30(–45) cm × (1–)2–4(–12) mm;
rachilla ± deciduous, wings 0.4–0.5 mm wide.
50–100, oblong-lanceoloid, ± terete-quadrangular, (3.5–)4–7 × 1–1.4 mm;
distal spikelet spreading or ascending;
floral scales persistent, 3–5, appressed, stramineous to brownish, 4-ribbed laterally, oblong-elliptic, 3.5–4.5 × 1–1.8 mm, membranous, apex entire or emarginate with mucro to 0.3 mm.
(5–)12–50, linear-lanceoloid, compressed, 5–30 × 0.6–0.9 mm;
floral scales ± deciduous, 3–11, appressed, medially green, laterally stramineous to pale brown, 3–4-ribbed laterally, (1–)3-ribbed medially, oblong-obovate, 3.2–4.5(–6) × 1–1.8 mm, apex ± acute, overlapping lower 1/4–1/2 of next scale.
anthers 0.4–0.8 mm;
styles 0.5–0.6 mm;
stigmas 1 mm.
anthers 0.3–0.5 mm;
styles 1–2 mm;
stigmas 3–4 mm.
brown, ± stipitate, oblong, (1.5–)1.8–2.3 × 0.5–0.6(–0.7) mm (1/2 length of floral scales), apex obtuse, surfaces puncticulate.
purplish brown, ± stipitate, narrowly oblong, (1.5–)1.8–2.4 × 0.5–0.6 mm, apex apiculate, acute, surfaces puncticulate.
Cyperus echinatus
Cyperus strigosus
The records for Rhode Island and Wisconsin are according to M. L. Horvat (1941); we have not seen specimens from those states.
Cyperus echinatus is usually recognized by its tight, nearly spheric spikes; it may occasionally be hard to distinguish from C. croceus and C. retrorsus. Compared to C. retrorsus, C. echinatus has larger spikelets and longer floral scales, anthers, and achenes. In contrast to C. echinatus, C. croceus has looser spikes, shorter, broader, greenish or yellowish floral scales, shorter, more ovoid achenes, and shorter anthers. Furthermore, C. echinatus is predominantly an inland species of roadsides, pastures, and other disturbed ground; C. retrorsus is primarily a coastal species and occurs in drier, sandier sites.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Cyperus strigosus is usually among the more common Cyperus species throughout its range. Small individuals flowering the first year may be difficult to distinguish from C. polystachyos, C. odoratus, C. erythrorhizos, and C. esculentus, which may be sympatric. Cyperus strigosus has trigonous achenes and three stigmas, unlike C. polystachyos; C. strigosus has flattened spikelets, unlike the subcylindric ones of C. odoratus; C. strigosus has floral scales usually 3 mm or more, unlike the smaller (1.2–1.5 mm) ones of C. erythrorhizos; C. strigosus has deciduous floral scales and a cormlike stem base with stolons, unlike C. esculentus.
Cyperus strigosus appears to be closely related to the neotropical C. camphoratus Liebmann; both species have deciduous floral scales and deciduous spikelets (G. C. Tucker 1994). Plants segregated as C. stenolepis cannot be distinguished consistently from C. strigosus on any single charcter, rather they appear to be merely large individuals of C. strigosus with long floral scales and frequently septate inflorescence bracts (M. L. Horvat 1941).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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