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Asian flatsedge, smallflower umbrella sedge, variable flatsedge

Alabama swamp flatsedge

Habit Herbs, annual, cespitose. Herbs, perennial, solitary or cespitose, rhizomatous, coarse.
Culms

1–15, trigonous, 7–30 cm × 1.2–2.5 mm, soft (flattened in pressing), glabrous.

trigonous, (30–)60–130 cm × 1–4(–9) mm, densely papillose, otherwise glabrous.

Leaves

2–7, flat, (2–)7–22 cm × 2.2–4 mm.

with cross ribs prominent, V-shaped, 30–100 cm × 5–13(–20) mm, margins, keel incisive with brownish prickles, papillose throughout, margins and midribs harshly scabrid.

Inflorescences

heads dense, 7–17 mm diam.; when rays short, heads sessile or nearly so, then densely irregularly lobate, 12–35 mm diam.;

rays 1–5, 2–32 mm;

bracts 2–4, longest bract erect or nearly so, appearing as continuation of culm, other bracts horizontal to ascending, 1–22 cm × 0.5–3.5 mm, margins and keel minutely scabridulous.

spikes 3–7, densely oblong-cylindric to ± globose, 10–28(–35) × 8–12(–15) mm;

rays 5–12, 1–16 cm, densely papillose;

bracts 5–12, ascending at 30–75°, flat to V-shaped, 4–50(–90) cm × 1–15 mm;

rachilla deciduous, wings persistent, (0.2–)0.3–0.5(–0.6) mm.

Spikelets

30–120, greenish brown to purplish brown, oblong-ellipsoid, compressed, (2–)3–5(–6) × 0.8–1.2 mm;

floral scales (6–)12–20(–30), laterally clear margins, stramineous to deep purple, medially greenish, stramineous, or purplish, laterally ribless, medially 3-ribbed, obovate to orbiculate, 0.6–0.8 × 0.6–0.8 mm, apex mucronulate.

20–80, oblong-ellipsoid, ± terete, slightly compressed, 3–7 × 1–2(–2.7) mm;

distal spikelets spreading or ascending;

floral scales (2–)4–7, appressed, clear to brownish, reddish streaked, medially green, 9–11-ribbed, ovate, (2–)2.5–3.3 × 1.2–2.3 mm, apex acute, mucronate.

Flowers

stamens 1 or 2;

anthers ovoid-ellipsoid, 0.1 mm, connective not prolonged;

styles 0.1 mm;

stigmas 0.1–0.3 mm.

anthers 0.6–0.8 mm, styles 0.5–1 mm;

stigmas 1–2.3 mm.

Achenes

light brown, obovoid-ellipsoid, 0.6–0.8 × 0.3–0.4 mm (as long as subtending scale), base cuneate, apex obtuse, apiculate, surfaces finely reticulate, papillose.

brown, slightly stipitate, obovoid to broadly ellipsoid, (1.2–)1.5–1.6(–1.7) × 0.6–0.8 mm, apex apiculate, surfaces puncticulate.

Cyperus difformis

Cyperus ligularis

Phenology Fruiting summer. Fruiting throughout the year.
Habitat Disturbed, muddy soils, shallow waters Beaches, brackish marshes, mangrove swamps, disturbed soils, ditches, riverbanks, coastal croplands
Elevation 0–1000 m (0–3300 ft) 0 m (0 ft)
Distribution
from FNA
AL; AZ; CA; FL; GA; ID; KY; LA; MS; NC; NJ; NM; OR; PA; SC; TN; TX; VA; Mexico; South America; West Indies (Puerto Rico); Central America (Nicaragua, Panama); Eurasia; Indian Ocean Islands; Pacific Islands; Australia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
FL; Mexico; Central America; South America; w Africa
[WildflowerSearch map]
[BONAP county map]
Discussion

Cyperus difformis is naturalized in the New World and native to the Old World, where it ranges from southern Europe to southern Africa and eastward to Southeast Asia and Australia.

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

The papillose culms, rays, and leaves of Cyperus ligularis distinguish it from all other North American species of Cyperus.

Reports of Cyperus ligularis from California (G. C. Tucker 1993b) were based on specimens of C. owanii.

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

Source FNA vol. 23, p. 156. FNA vol. 23, p. 190.
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. 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. 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. 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. lateriflorus Mariscus rufus
Name authority Linnaeus: Cent. Pl. II, 6. (1756) Linnaeus: Syst. Nat. ed. 10, 2: 867. (1759)
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