Cyperus lupulinus
Cyperus strigosus
Great Plains flatsedge, slender sand sedge
false flatsedge, false nutsedge, straw color cyperus, straw-color flatsedge, straw-colour flatsedge
trigonous, (3–)10–50 cm × 0.4–1.2 mm, glabrous.
basally swollen and cormlike, trigonous, (1–)20–40(–90) cm × 1–6 mm, glabrous or few prickles subapically.
flat, 5–40 cm × 1–3.5 mm.
flat, (10–)20–40 cm × 1–4(–8) mm, margins and midribs glabrous or scabridulous.
spikes rather densely ovoid to globose, 1.2–3.5 cm;
rays 0 or 1–4, 1–6 cm;
rachis 1–3.5 mm;
bracts 2–4, horizontal to reflexed, flat, 6–25 cm;
rachilla ± deciduous, wingless.
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.
15–60, compressed, oblong-lanceoloid, (3–)6–22 × 2.5–4 mm;
floral scales deciduous, 5–22, off-white to light reddish brown, laterally 3–5-ribbed, ovate-elliptic, 2.5–4 × 2–2.6 mm, margins loosely spreading or clasping achene, apex entire to mucronate, mucro 0.05–0.2 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 0.3–0.6 mm;
styles 1 mm;
stigmas 1–1.5 mm.
anthers 0.3–0.5 mm;
styles 1–2 mm;
stigmas 3–4 mm.
dark brown or black, sessile, oblong-ellipsoid to ellipsoid, 1.7–2.2 × 0.8–1.2 mm, apex obtuse, apiculate, surfaces puncticulate.
purplish brown, ± stipitate, narrowly oblong, (1.5–)1.8–2.4 × 0.5–0.6 mm, apex apiculate, acute, surfaces puncticulate.
= 166.
Cyperus lupulinus
Cyperus strigosus
Subspecies 2 (2 in the flora).
Cyperus lupulinus was studied in detail (B. G. Marcks 1974). Ranges of the two subspecies overlap somewhat. Cyperus lupulinus subsp. lupulinus is found chiefly in the Great Plains, and subsp. macilentus is centered in the Northeast. It is seldom difficult to assign specimens to subspecies.
The hybrid of Cyperus lupulinus with C. schweinitzii is C. ×mesochorus Geise. It is occasionally encountered with the two parent species in the north-central states (Illinois, Indiana, Michigan, Minnesota, and Wisconsin) and has been recorded once from Quebec. The hybrid is similar in size to C. schweinitzii; it has fewer rays, inflorescence bracts 30–45º above horizontal, and floral scales with mucros 0.4–0.5 mm.
(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.)
1. Floral scales 2.5–4 mm, margins not clasping achene; spikelets with 5–22 floral scales. | subsp. lupulinus |
1. Floral scales 1.8–2.5 mm, margins tightly clasping achene; spikelets with 3–7 floral scales. | subsp. macilentus |
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- Encyclopedia of Life
- Wikipedia
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