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umbrella-plant

annual sedge, poorland flatsedge

Habit Herbs, perennial, cespitose, rhizomatous. Herbs, annual, cespitose with fibrous roots.
Culms

trigonous, 30–150 cm × 1–5(–8) mm.

trigonous, (2–)6–15(–35) cm × (0.3–)1–1.8 mm, glabrous.

Leaves

bladeless.

1–5, flat to V-shaped, (1–)5–15(–22) cm × (0.5–)1.5–3 mm.

Inflorescences

heads digitate, 15–30(–36) mm diam.;

rays (14–)20–22, (2–)5–12(–20) cm; 2d order rays 0.3–3(–4) cm; 3d order rays sometimes present, 0.3–2.5 cm;

bracts (4–)18–22, ± horizontal, flat, 15–27 cm × (1.5–)8–12 mm.

spikes ± digitate, ± globose, 7–40 × 10–20 mm;

rays (0–)1–6, 2–12 cm;

if absent, inflorescence a sessile cluster of (1–)3–10 spikelets;

rachis 2–5 mm;

bracts (1–)4–5(–6), ascending, V-shaped, 1–15(–20) cm × 0.5–3.5 mm;

rachilla persistent, wingless.

Spikelets

8–20, ovoid to linear-lanceoloid, compressed, 5–25 × 1.5–2 mm;

floral scales 8–28, laterally whitish or light brown, ± hyaline, medially light brown, laterally ribless, medially 3-ribbed, 2-keeled in proximal 30–60%, deltate-ovate, 1.6–2.4 × (1–)1.2–1.5(–1.7) mm, apex acute.

(1–)3–12(–16), greenish white, linear to linear-lanceoloid, compressed-quadrangular, 6–34(–40) × 2–3(–3.6) mm;

floral scales deciduous, (8–)16–36(–42), spreading, laterally whitish, greenish, or pale brownish, medially green, weakly 7–9-ribbed, laterally weakly 1–2-ribbed, most ribs medial, ovate, (2.4–)2.6–3 × (1.9–)2–2.4(–2.5) mm, apex acute to ± acute, cuspidate tip (0.3–)0.5–0.7(–0.8) mm.

Flowers

stamens 3;

anthers 0.7–1 mm;

styles 0.5–1 mm;

stigmas 0.6–1 mm.

anthers 0.6–0.7 mm;

styles 0.9–1.3 mm;

stigmas 0.5–0.8 mm.

Achenes

brown, sessile or stipitate, broadly ellipsoid, 0.6–0.8 × 0.4–0.6 mm, stipe if present to 0.1 mm, apex obtuse, apiculate, surfaces puncticulate.

brown, stipitate to sessile, obovoid, (1–)1.2–1.4(–1.5) × 0.9–1(–1.1) mm, apex obtuse to emarginate, surfaces very finely puncticulate.

Cyperus involucratus

Cyperus compressus

Phenology Fruiting early summer–fall. Fruiting summer–early fall.
Habitat Damp, disturbed soils, ditches, stream banks Various disturbed soils
Elevation 0–100(–800) m [0–300(–2600) ft] 0–900 m [0–3000 ft]
Distribution
from FNA
CA; FL; LA; TX; e Africa [Introduced in North America]
[BONAP county map]
from FNA
AL; AR; DE; FL; GA; IL; LA; MD; MO; MS; NC; NY; OH; PA; SC; TX; VA; Mexico; Central America; South America; Asia; Africa
[WildflowerSearch map]
[BONAP county map]
Discussion

Cyperus involucratus has been collected in New York (R. S. Mitchell and G. C. Tucker 1997).

Cyperus involucratus is widely cultivated as a water plant in greenhouses and outdoors in warm-temperate or tropical climates. It has long been misidentified in the flora as C. alternifolius Linnaeus, an endemic of Madagascar (G. C. Tucker 1983).

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

Source FNA vol. 23, p. 150. Treatment authors: Gordon C. Tucker*, Brian G. Marcks*, J. Richard Carter *. FNA vol. 23, p. 171. Treatment authors: Gordon C. Tucker*, Brian G. Marcks*, J. Richard Carter *.
Parent taxa Cyperaceae > Cyperus > subg. Pycnostachys 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. 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. 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. compressus var. pectiniformis, C. pectinatus, C. pectiniformis
Name authority Rottbøll: Descr. Pl. Rar., 22. (1772) Linnaeus: Sp. Pl. 1: 46. (1753)
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