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Rio Grande sedge

wiry flatsedge

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

trigonous, basally tuberous thickened, 15–40 cm × 1–2.5 mm, glabrous.

trigonous, 20–36 cm × 0.5–1 mm.

Leaves

flat to V-shaped, 10–30 cm × 1–2 mm.

flat, 4–22 cm × 1–2 mm.

Inflorescence(s)

spike 1, densely oblong to ellipsoid, 8–36 × 8–20 mm;

rays 4–12, 10–20 cm;

bracts 3–6, horizontal to ascending at 30°, V-shaped, 3–15 cm × (3–)4–5.8 mm;

rachilla deciduous, wings 0.5–0.7 mm wide.

a single loose cluster of spikelets;

rays 0–(1–2), if present, to 4 cm;

bracts 2–3, ascending, 1–8 cm × 0.7–1 mm;

rachilla with wings 0.6 mm wide.

Spikelets

(5–)20–35(–60), linear to oblong, quadrangular; 4–12(–21) × 0.7–1.2 mm, base narrowed to 0.4–1 mm;

floral scales persistent, 1–3(–5), appressed, laterally whitish to reddish brown, stramineous with reddish spots, medially green, laterally 3–6-ribbed (midrib distinctly scabrid at 30X), narrowly oblong to ovate, 2.6–4.8 × 1.6–2 mm;

apex rounded to ± acute, entire, with mucro 0.3–0.5 mm;

sterile terminal scale involute, 0.4–0.6 mm wide, uncinate;

distal floral scales with cusp 0.6–1.9.

2–8, linear, terete, 6–20 × 0.7–1 mm;

floral scales 6–10, medially green, laterally brown, medially faintly 3-ribbed, laterally faintly 3–5-ribbed, ovate, 2.5–3 × 2 mm.

Flowers

anthers 0.5–1.3 mm;

styles 0.4–0.5 mm;

stigmas 0.5–0.9 mm.

anthers 1 mm;

styles 0.5 mm;

stigmas 1 mm.

Achenes

light brown to reddish brown, sessile to slightly stipitate, narrowly ellipsoid, 1.8–2.4 × 0.6–0.8 mm, apex slightly apiculate, surfaces puncticulate.

black, sessile, obovoid, 2 × 0.8 mm, apex scarcely apiculate, surfaces puncticulate.

Cyperus floribundus

Cyperus filiformis

Phenology Fruiting mid summer–early fall (Jul–Sep). Fruiting spring–fall.
Habitat Damp, disturbed soils, croplands Damp, disturbed places
Elevation 0–1000 m (0–3300 ft) 0–20 m (0–100 ft)
Distribution
from FNA
TX; Mexico
[BONAP county map]
from FNA
FL; West Indies
[BONAP county map]
Discussion

Included previously in Cyperus retroflexus (or its synonym C. uniflorus), C. floribundus has a much narrower geographic range (southern Texas and northeastern Mexico) and differs in features of spikelet morphology (J. R. Carter and S. D. Jones 1997).

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

Source FNA vol. 23. FNA vol. 23.
Parent taxa Cyperaceae > Cyperus > subg. Cyperus Cyperaceae > Cyperus > subg. Diclidium
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. 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. 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. uniflorus var. floribundus, C. uniflorus C. floridanus, Mariscus filiforme, Mariscus floridensis, Torulinium filiforme
Name authority (Kükenthal) J. Rich. Carter & S. D. Jones: Rhodora 99: 330. (1998) Swartz: Prodr., 20. (1788)
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