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false flatsedge, false nutsedge, straw color cyperus, straw-color flatsedge, straw-colour flatsedge

Owan's flatsedge

Habit Herbs, perennial (often flowering first year), rhizomatous. Herbs, perennial, cespitose, rhizomatous.
Culms

basally swollen and cormlike, trigonous, (1–)20–40(–90) cm × 1–6 mm, glabrous or few prickles subapically.

roundly trigonous, 80–120 cm × 3–6 mm, glabrous.

Leaves

flat, (10–)20–40 cm × 1–4(–8) mm, margins and midribs glabrous or scabridulous.

5–12, V-shaped, 30–75 cm × 8–14 mm, septate, leathery, margins harshly scabrid.

Inflorescences

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.

spikes 1–4 per ray, loosely ovoid to broadly ellipsoid, 12–20 × 8–12 mm;

rays 6–9, 3–10(–12) cm; 2d order rays 1–4, 1–2 cm;

rachis 4–12 mm;

bracts 5–10, horizontal to ascending at 30°, 15–40 cm × 4–8(–11) mm;

rachilla deciduous, wings persistent, hyaline, fragile, 0.3 mm wide, covering less than 1/2 of achene.

Spikelets

(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.

40–80, narrowly ellipsoid to ellipsoid, roughly quadrangular to weakly flattened, 5–8 × 1.2–1.5 mm;

distal spikelet spreading or ascending;

floral scales (1–)2(–3), ascending, brick red, medially greenish, laterally 3–4-ribbed, medially 1–3-ribbed, green, ovate, 2.2–3.5 × 1.5–1.8 mm, apex subacute.

Flowers

anthers 0.3–0.5 mm;

styles 1–2 mm;

stigmas 3–4 mm.

anthers (0.7–)1–1.5 mm, filaments 4–4.7 mm;

styles 0.5–0.9 mm;

stigmas 2–3 mm.

Achenes

purplish brown, ± stipitate, narrowly oblong, (1.5–)1.8–2.4 × 0.5–0.6 mm, apex apiculate, acute, surfaces puncticulate.

brown, ellipsoid to oblong-fusiform, 1.7–1.8 × 0.7 mm, base cuneate, apex subacute and apiculate, surfaces finely puncticulate to glabrous.

Cyperus strigosus

Cyperus owanii

Phenology Fruiting summer. Fruiting spring–fall.
Habitat Pond shores, ditches, damp, disturbed soils, sometimes weeds of gardens or croplands Disturbed, damp thickets, open woods
Elevation 0–1500 m (0–4900 ft) 0–200 m (0–700 ft)
Distribution
from FNA
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; MB; ON; QC; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; s Africa [Introduced in North America]
[BONAP county map]
Discussion

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.)

Cyperus owanii is easily distinguished from other sedges in California by the large size, reddish spikelets, and secondary rays. It was first collected in California in 1938.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 23, p. 184. FNA vol. 23, p. 184.
Parent taxa Cyperaceae > Cyperus > subg. Cyperus Cyperaceae > Cyperus > subg. Cyperus
Sibling taxa
C. acuminatus, C. aggregatus, C. alopecuroides, C. amabilis, C. articulatus, C. bipartitus, C. cephalanthus, C. compressus, C. croceus, C. cuspidatus, C. dentatus, C. dentoniae, C. diandrus, C. difformis, C. digitatus, C. dipsaceus, C. distans, C. distinctus, C. drummondii, C. echinatus, C. elegans, C. entrerianus, C. eragrostis, C. erythrorhizos, C. esculentus, C. fendlerianus, C. filicinus, C. filiculmis, C. filiformis, C. flavescens, C. flavicomus, C. floribundus, C. fugax, C. fuligineus, C. fuscus, C. giganteus, C. gracilis, C. granitophilus, C. grayi, C. grayoides, C. haspan, C. hermaphroditus, C. houghtonii, C. hypopitys, C. hystricinus, C. involucratus, C. iria, C. laevigatus, C. lancastriensis, C. lanceolatus, C. lecontei, C. lentiginosus, C. ligularis, C. lupulinus, C. manimae, C. microiria, C. mutisii, C. niger, C. ochraceus, C. odoratus, C. onerosus, C. ovatus, C. owanii, C. oxylepis, C. pallidicolor, C. papyrus, C. parishii, C. pilosus, C. planifolius, C. plukenetii, C. polystachyos, C. prolifer, C. prolixus, C. pseudothyrsiflorus, C. pseudovegetus, C. pumilus, C. reflexus, C. refractus, C. retroflexus, C. retrofractus, C. retrorsus, C. rotundus, C. sanguinolentus, C. schweinitzii, C. serotinus, C. seslerioides, C. setigerus, C. spectabilis, C. sphacelatus, C. sphaerolepis, C. squarrosus, C. surinamensis, C. tetragonus, C. thyrsiflorus, C. virens
C. acuminatus, C. aggregatus, C. alopecuroides, C. amabilis, C. articulatus, C. bipartitus, C. cephalanthus, C. compressus, C. croceus, C. cuspidatus, C. dentatus, C. dentoniae, C. diandrus, C. difformis, C. digitatus, C. dipsaceus, C. distans, C. distinctus, C. drummondii, C. echinatus, C. elegans, C. entrerianus, C. eragrostis, C. erythrorhizos, C. esculentus, C. fendlerianus, C. filicinus, C. filiculmis, C. filiformis, C. flavescens, C. flavicomus, C. floribundus, C. fugax, C. fuligineus, C. fuscus, C. giganteus, C. gracilis, C. granitophilus, C. grayi, C. grayoides, C. haspan, C. hermaphroditus, C. houghtonii, C. hypopitys, C. hystricinus, C. involucratus, C. iria, C. laevigatus, C. lancastriensis, C. lanceolatus, C. lecontei, C. lentiginosus, C. ligularis, C. lupulinus, C. manimae, C. microiria, C. mutisii, C. niger, C. ochraceus, C. odoratus, C. onerosus, C. ovatus, C. oxylepis, C. pallidicolor, C. papyrus, C. parishii, C. pilosus, C. planifolius, C. plukenetii, C. polystachyos, C. prolifer, C. prolixus, C. pseudothyrsiflorus, C. pseudovegetus, C. pumilus, C. reflexus, C. refractus, C. retroflexus, C. retrofractus, C. retrorsus, C. rotundus, C. sanguinolentus, C. schweinitzii, C. serotinus, C. seslerioides, C. setigerus, C. spectabilis, C. sphacelatus, C. sphaerolepis, C. squarrosus, C. strigosus, C. surinamensis, C. tetragonus, C. thyrsiflorus, C. virens
Synonyms C. hansenii, C. stenolepis, C. strigosus var. hansenii, C. strigosus var. stenolepis, Mariscus stenolepis, Mariscus strigosus Mariscus umbilensis
Name authority Linnaeus: Sp. Pl. 1: 47. (1753) Boeckeler: Flora 61: 29. (1878)
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