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Texas flatsedge

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

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

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

Leaves

flat, 10–30 cm × 0.5–2 mm.

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

Inflorescences

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.

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.

Spikelets

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.

(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.

Flowers

anthers 0.8–1 mm;

styles 1 mm;

stigmas 1.5–2.5 mm.

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.

Achenes

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

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

Cyperus filiculmis

Cyperus seslerioides

Phenology Fruiting summer. Fruiting summer.
Habitat Well-drained, open roadsides, fields, pine barrens, dunes Seeps, damp meadows in montane forests
Elevation 0–200 m (0–700 ft) 1000–2000 m (3300–6600 ft)
Distribution
from FNA
AL; FL; GA; LA; MD; MS; NC; SC; TX; VA
from FNA
AZ; TX; Mexico; South America; Central America (Honduras)
[BONAP county map]
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. 175. FNA vol. 23, p. 157.
Parent taxa Cyperaceae > Cyperus > subg. Cyperus 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. 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
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
Synonyms C. martindalei
Name authority Vahl: Enum. Pl. 2: 328. (1805) Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 209. (1816)
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