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rough flatsedge

foxtail flatsedge

Habit Herbs, perennial, cespitose. Herbs, perennial, rhizomatous, coarse.
Culms

with cormlike bases, sharply trigonous, 25–90 cm, glabrous proximally, minutely scabridulous distally.

trigonous, 150–250 cm × 2–15 mm, glabrous.

Leaves

V-shaped, 14–40 cm × 3.5–8 mm, (pubescent on adaxial side of midrib).

inversely W-shaped, 30–150 cm × 6–22 mm.

Inflorescences

spikes loose, obtrulloid to obdeltoid (broadest near apex, nearly as long as wide), 20–28(–34) × (12–)15–30 mm;

rays 4–13, (1–)4–24 cm (longest ray shorter than bracts), glabrous;

bracts 3–12, ascending at 30–45°, flat, 3–25 cm × 3–7 mm;

rachilla persistent, wings 0.4–0.6 mm wide, covering 3/4 of mature achene.

spikes 1–4, cylindric, 1.5–4 cm × 7–15 mm;

rays 3–9, 10–26 cm; 2d order rays 2–11 cm; 3d order rays 1–4 cm (or absent);

bracts 3–5, ± horizontal, 20–100 cm × 3–15 mm; 2d order bracts 2–7 cm × 2–7 mm; 3d order bracts 2–5 cm × 2–4 mm (or absent);

rachilla persistent, wingless or wing hyaline, narrow, 0.1 mm wide.

Spikelets

30–50, proximal one reflexed, distal ones divaricate, linear-lanceoloid, ± terete, (6.5–) 8–10(–17) × 0.5–0.7 mm;

floral scales persistent, 3–6(–8), appressed, stramineous (suffused with reddish purple), 4–5-ribbed laterally, ovate-lanceolate, (4–)4.4–4.9(–5.4) × 1.3–1.5 mm;

terminal scale not spinose, apex straight, excurved mucronate, or cuspidate.

50–100, linear, ± quadrangular, slightly compressed, 8–11 × 0.9–1.2 mm;

floral scales 15–30, marginally clear, laterally reddish along midrib, medially green, laterally 3–4 ribbed, medially 3–5-ribbed, ovate, 1–2–1.6 × 1.1–1.3 mm, apex mucronulate.

Flowers

anthers 0.7–1.2 mm;

styles 1.5–2 mm;

stigmas 2–2.5 mm.

anthers 2, 0.4–0.5 mm;

styles 0.8–1 mm;

stigmas 2, 0.4 mm.

Achenes

brown to brownish black, narrowly oblong, (2.2–)2.5–3 × 0.6–0.7 mm, base cuneate, apex obtuse, apiculate, surfaces puncticulate.

dark brown, sessile, ellipsoid to obovoid, 0.9 × 0.4–0.5 mm, surfaces finely puncticulate.

Cyperus retrofractus

Cyperus alopecuroides

Phenology Fruiting summer. Fruiting summer.
Habitat Roadsides, pastures, disturbed sites in sandy or clayey soils Pond shores, stream banks
Elevation 0–300 m (0–1000 ft) 0–30 m (0–100 ft)
Distribution
from FNA
AL; AR; DC; DE; GA; KY; MO; NC; NJ; OH; PA; SC; TN; VA
[WildflowerSearch map]
[BONAP county map]
from FNA
FL; West Indies; Asia; Africa; Australia [Introduced in North America]
[BONAP county map]
Discussion

For information concerning nomenclature of Cyperus retrofractus, see J. R. Carter and C. E. Jarvis (1986).

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

Cyperus alopecuroides has been introduced in Polk County, Florida.

Plants of Cyperus alopecuroides might be confused with C. digitatus; large size and the biconvex achenes with two stigmas characterize C. alopecuroides.

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

Source FNA vol. 23, p. 180. FNA vol. 23, p. 173.
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. 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. 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. strigosus, C. surinamensis, C. tetragonus, C. thyrsiflorus, C. virens
Synonyms Scirpus retrofractus, C. dipsaciformis, C. retrofractus var. dipsaciformis, Mariscus retrofractus
Name authority (Linnaeus) Torrey: in J. Carey, Carices North. U.S., 519. (1847) Rottbøll: Descr. Pl. Rar., 20. (1772)
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