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umbrella flat sedge

tooth flatsedge

Habit Herbs, annual, cespitose, with fibrous roots. Herbs, perennial, cespitose, rhizomatous; stolons tuberiferous, 1–10 cm.
Culms

trigonous, 4–25(–35) cm, glabrous.

trigonous, 8–50 cm × 1–3 mm.

Leaves

flat, 5–20 cm × 1.5–3 mm.

flat or V-shaped, 10–40 cm × 2–5 mm.

Inflorescences

heads ± digitate, 12–22 mm diam.;

rays 3–6, 1–6 cm;

bracts 1–4, ± horizontal, flat, 1.5–15 cm × 1.5–3 mm.

heads digitate, 8–18 mm diam.;

rays 4–9, 1–8 cm; 2d order rays 0.5–2 cm;

bracts 3–5, ± horizontal, flat, 1–20 cm × 1–4 mm.

Spikelets

6–12, oblong-lanceoloid, compressed, 5–10 × 2.8–3.2 mm;

floral scales 8–28, closely imbricate, stramineous to light brown or clear (marginal band bright red, spikelet thus appearing dark margined), laterally ribless, oblong to ovate, 2.5–3 × 1.6–1.9 mm.

commonly proliferous, 2–6, linear to oblong, compressed, 3–24 × 2–2.5 mm;

floral scales 3–20(–50), reddish brown, laterally 1–3-ribbed, ovate, 2–2.5 × 1.5–2 mm.

Flowers

stamens 2(–3);

anthers 0.3 mm, connective apex reddish, subulate, 0.1–0.2 mm;

styles 0.3–0.5 mm;

stigmas 2.2–3.1 mm.

stamens 3;

anthers 1.5 mm;

styles 1 mm;

stigmas 1.5 mm.

Achenes

brown, network of ridges forming isodiametric or square cells, sessile or stipitate, obovoid to ovoid, 1–1.2 × 0.5–0.6 mm, stipe, if present, 0.1 mm, apex obtuse, apiculate, surfaces minutely punctate.

reddish brown, sessile, obovoid, 0.8–1 × 0.4–0.5 mm, apex obtuse, scarcely apiculate, surfaces glabrous.

Cyperus diandrus

Cyperus dentatus

Phenology Fruiting summer. Fruiting summer.
Habitat Emergent shorelines, in sandy, peaty, or slightly brackish areas (though seldom where disturbed) Emergent sandy, peaty, or gravelly shorelines
Elevation 0–600 m (0–2000 ft) 0–600 m (0–2000 ft)
Distribution
from FNA
CT; DE; IA; IL; IN; MA; MD; ME; MI; MN; MO; NE; NH; NJ; NY; PA; RI; VA; VT; NB; NS; ON; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; DC; DE; IN; MA; MD; ME; NC; NH; NY; PA; RI; SC; TN; VA; VT; NB; NS; ON; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

The report of Cyperus dentatus from West Virginia (M. V. McGivney 1938) is erroneous; the cited specimen was from New Jersey (Gutenberg s.n. 1886, US) (M. Strong, pers. comm.).

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

Source FNA vol. 23, p. 161. FNA vol. 23, p. 151.
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. 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
C. acuminatus, C. aggregatus, C. alopecuroides, C. amabilis, C. articulatus, C. bipartitus, C. cephalanthus, C. compressus, C. croceus, C. cuspidatus, 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 Pycreus diander
Name authority Torrey: Cat. Pl. New York, 90. (1819) Torrey: Fl. N. Middle United States 1: 61. (1824)
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