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Texas flatsedge

Habit Herbs, perennial, cespitose; rhizomes knotty, much branched, 2–5 mm diam., scaly. Herbs, perennial, cespitose, bases cormose; rhizomes knotted, beaded.
Culms

roundly trigonous, basally with dark fibrous remnants of old leaf sheaths, (0.5–)4–30 cm × 0.4 –1.1 mm, glabrous.

trigonous, 15–48 cm × 0.4–1 mm, glabrous.

Leaves

1–5, flat, involute toward apex, 3–18 cm × 1–2.5(–3) mm.

flat, 10–30 cm × 0.5–2 mm.

Inflorescences

heads hemispheric to spheric, (3–)6–15(–24) mm diam.;

rays absent;

bracts 2–5, horizontal to reflexed, parallel to culm, 1–13 cm × 1–3 mm, margins and keel sparsely minutely scabridulous distally.

spikes rather densely ovoid, 1–3.5 cm;

rays 0 (sometimes 1–4), 1–6 cm;

rachis 1–4 mm;

bracts 3–4, horizontal to slightly reflexed, flat, 6–25 cm;

rachilla ± deciduous, wingless.

Spikelets

(5–)20–60(–100), whitish to greenish or brownish, ovoid to oblong-lanceoloid, compressed, 3–7 × 2–4 mm;

floral scales (8–)10–12(–24), laterally milky white (infrequently yellowish, pale greenish, brown, or bronze-white), medially green or white, laterally ribless, medially 3-ribbed, ovate to ovate-lanceolate, 1.6–3(–3.4) × 0.8–1.3 mm, apex mucronate to acuminate.

25–60, compressed, oblong-lanceoloid, 5–12 × 2.2–3.5 mm;

floral scales deciduous, 5–15, yellowish to yellowish brown, laterally 4–5-ribbed, oblong-ovate, 2.6–3.6 × 1.4–2 mm, margins loosely spreading or clasping achene.

Flowers

stamens 3;

anthers linear, (0.4–)0.6–0.8(–1.1) mm, connective not prolonged;

styles 0.8–1.8 mm;

stigmas (0.5–)1–1.5(–2) mm.

anthers 0.8–1 mm;

styles 1 mm;

stigmas 1.5–2.5 mm.

Achenes

brown to blackish, trigonous, broadly obovoid, 0.5–1 × 0.3–0.75 mm, base slightly stipelike, ± cuneate to rounded, apex apiculate, papillose.

dark grayish brown, sessile, narrowly oblong, 1.8–2.2 × 0.5–0.8 mm, apex obtuse, apiculate, surfaces puncticulate.

Cyperus seslerioides

Cyperus filiculmis

Phenology Fruiting summer. Fruiting summer.
Habitat Seeps, damp meadows in montane forests Well-drained, open roadsides, fields, pine barrens, dunes
Elevation 1000–2000 m (3300–6600 ft) 0–200 m (0–700 ft)
Distribution
from FNA
AZ; TX; Mexico; South America; Central America (Honduras)
[BONAP county map]
from FNA
AL; FL; GA; LA; MD; MS; NC; SC; TX; VA
Discussion

Cyperus filiculmis has long been treated within a broader and more widely used concept of C. filiculmis (C. lupulinus); see B. G. Marcks (1974)

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

Source FNA vol. 23, p. 157. FNA vol. 23, p. 175.
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. 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. 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. 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. martindalei
Name authority Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 209. (1816) Vahl: Enum. Pl. 2: 328. (1805)
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