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many-spike flatsedge

foothill flatsedge

Habit Herbs, perennial (annual?), cespitose. Herbs, annual, cespitose.
Culms

trigonous or ± terete, (3–)20–45(–70) cm × (0.8–) 1.2–2 mm, glabrous.

1–10(–25), roundly trigonous, 3–12 cm × 0.3–0.8 mm, glabrous.

Leaves

(2–) 6–10(–16), flat to V-shaped, (2–) 10–30(–60) cm × 1–4 mm.

1–3–(4), 1–6 cm × 1(–1.5) mm.

Inflorescences

spike 1, loosely ovoid to densely turbinate, 12–40 × 10–25 mm;

rachis 3–10 mm;

rays 1–8(–12), 0.5–3(–6) cm; 2d order rays absent;

if rays absent, inflorescence single dense cluster of spikelets, 12–40 mm diam.;

bracts (3–)4–6(–7), horizontal to ascending at 45°, flanged V-shaped, (2–)5–15(–23) cm × 1–4 mm.

if rays absent heads single, dense, sessile, digitate, 5–20 × 10–30 mm, single heads 10–30(–50) mm;

rays usually absent, if present 1–8 cm; 2d order rays infrequently present, 1–2 cm;

bracts 3–6, erect to oblique, flat to V-shaped,(0.5–)2–10(–15) cm × 0.5–2 mm.

Spikelets

(5–)15–30(–40), spreading to appressed-ascending, linear-lanceoloid to linear, compressed, 8–18(–40) × (1–)1.3–1.6(–2) mm;

floral scales (8–)12–25(–66), laterally stramineous to light brown, medially green, laterally ribless, medially 3–5-ribbed, oblong, (1.5–)1.8–2.4 × (1–)1.2–1.4 mm, apex acute to ± acute, mucronate.

5–10(–20), linear to linear-lanceoloid, (5–)8–12(–35) × 1.6–2.3(–2.5) mm;

floral scales (6–)16–30(–76), laterally glossy reddish brown to brown, medially greenish, sometimes also reddish or brownish, laterally ribless, medially strongly 3-ribbed, ovate-lanceolate, 1.9–2(–2.3) mm (including prominent excurved cusp of 0.3–0.5 mm) × 0.8–1.1 mm, apex truncate, emarginate, or cuspidate.

Flowers

stamens 2;

anthers (0.4–)0.5–0.8 mm, connective not prolonged;

styles 0.6–1(–1.4) mm;

stigmas (1–)1.4–2 mm.

stamens (1–)2–3;

anthers ellipsoid, 0.3 mm, connectives not prolonged;

styles 0.3–0.4 mm;

stigmas 0.4–0.7 mm.

Achenes

light to dark brown, oblong, (0.8–)0.9–1.1(–1.2) × 0.4–0.5(–0.6) mm, base cuneate to ± stipelike, apex truncate, apiculate, surfaces punctate to minutely punctate with raised cells.

brown, slightly stipitate, obovoid to oblong, 0.8–0.9 × 0.4–0.5 mm, apex abruptly apiculate, surfaces papillose.

Cyperus polystachyos

Cyperus amabilis

Phenology Fruiting summer–early fall. Fruiting summer.
Habitat Shores, ditches, swales between dunes Seasonally wet, sandy soils
Elevation 0–200 m (0–700 ft) 500 m (1600 ft)
Distribution
from FNA
AL; DC; DE; FL; GA; KY; LA; MA; MD; ME; MS; NC; NJ; NY; OK; PA; SC; TX; VA; WV; Mexico; Central America; South America; Asia; Africa
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; Mexico; Central America; South America; Asia; Africa
[BONAP county map]
Discussion

Cyperus polystachyos is polymorphic. Adequate understanding of the infraspecific variations of C. polystachyos requires a worldwide examination, which is beyond the scope of this study. The segregates, C. fugax and C. filicinus, are recognized here; they have been usually accepted by recent workers (e.g., M. L. Fernald 1950; H. A. Gleason and A. Cronquist 1991).

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

Source FNA vol. 23, p. 160. FNA vol. 23, p. 158.
Parent taxa Cyperaceae > Cyperus > subg. Pycreus Cyperaceae > Cyperus > subg. Pycnostachys
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. 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
C. acuminatus, C. aggregatus, C. alopecuroides, 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. strigosus, C. surinamensis, C. tetragonus, C. thyrsiflorus, C. virens
Synonyms C. brizaeus, C. polystachyos var. leptostachyus, Pycreus polystachyos C. amabilis var. macrostachyus, C. aurantiacus, C. aureus, C. aureus var. aurantiacus, C. aureus var. macrostachyus, C. aureus var. oligostachyus, C. microstachyus, C. oligostachyus
Name authority Rottbøll: Descr. Pl. Rar., 21. (1772) Vahl: Enum. Pl. 2: 318. (1805)
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