FNA: Cyperus dentoniae

	Cyperus dentoniae
	Denton's flatsedge, hairy flatsedge
Habit	Herbs, perennial, cespitose, shortly rhizomatous.
Culms	1–4, trigonous, (2–)20–50(–80) cm × (0.8–)1.5–2(–2.8) mm, basally glabrous or nearly so, apically hispidulous, on faces and angles distally, especially so immediately proximal to bracts.
Leaves	2–5(–7), V-shaped, (5–)15–30(–45) cm × (1.5–)2.5–5(–8) mm.
Inflorescences	spike 1 (occasionally 1–2 smaller sessile spikes at base), densely cylindric, (7–)11–20(–25) × (5–) 7–10(–12) mm; rays 3–6(–10), (1–)3–6(–18) cm, rays and rachis hispidulous; bracts 4–8(–10), ascending at 30–60°, V-shaped, (2–)10–25(–45) cm × (1–)3–6(–8) mm; rachilla deciduous, wings persistent, 0.3–0.4 mm wide.
Spikelets	(20–)70–120(–140), oblong-ellipsoid to oblong-lanceoloid, ± terete to quadrangular, (2.2–)3.4–4.5(–5.6) × (0.8–)0.9–1.2(–1.3) mm; distal spikelet spreading or ascending; floral scales 1(–3), appressed, stramineous, red-spotted, strongly 3(–4)-ribbed on either side of green part, medially weakly 3-ribbed, ovate to elliptic ovate, (2.4–)2.8–3.3(–3.6) × 1.6–2 mm, apex acute, mucronulate from excurrent midrib.
Flowers	anthers (0.3–)0.4–0.6 mm; styles 0.4–0.6(–0.8) mm; stigmas 1–1.4 mm.
Achenes	brown, stipitate, ellipsoid, (1.6–)1.8–2 × (0.7–) 0.8–0.9 mm, stipe 0.1–0.2 × 0.2 mm, apex ± truncate, apiculate, surfaces puncticulate to glabrous.

	Cyperus dentoniae
Phenology	Fruiting mid summer–fall (Jul–Sep).
Habitat	Various dry, open environments
Elevation	500–1000 m (1600–3300 ft)
Distribution	AZ; Mexico; Central America; South America [BONAP county map]
Discussion	Cyperus dentoniae was not treated in G. Kükenthal’s monograph (1935–1936), apparently because he did not see any materials of the species. The plant has been treated as “C. asper (Liebmann) O’Neill,” a name based on Mariscus asper Liebmann and a synonym of C. mutisii (A. B. Ayers 1946). (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 23, p. 187.
Parent taxa	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. 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	Mariscus pubescens, C. flavomariscus var. peduncularis, C. flavus var. peduncularis
Name authority	G. C. Tucker: Syst. Bot. Monogr. 2: 56. (1983)
Web links	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Cyperus dentoniae

Denton's flatsedge, hairy flatsedge

Habit

Herbs, perennial, cespitose, shortly rhizomatous.

Culms

1–4, trigonous, (2–)20–50(–80) cm × (0.8–)1.5–2(–2.8) mm, basally glabrous or nearly so, apically hispidulous, on faces and angles distally, especially so immediately proximal to bracts.

Leaves

2–5(–7), V-shaped, (5–)15–30(–45) cm × (1.5–)2.5–5(–8) mm.

Inflorescences

spike 1 (occasionally 1–2 smaller sessile spikes at base), densely cylindric, (7–)11–20(–25) × (5–) 7–10(–12) mm;

rays 3–6(–10), (1–)3–6(–18) cm, rays and rachis hispidulous;

bracts 4–8(–10), ascending at 30–60°, V-shaped, (2–)10–25(–45) cm × (1–)3–6(–8) mm;

rachilla deciduous, wings persistent, 0.3–0.4 mm wide.

Spikelets

(20–)70–120(–140), oblong-ellipsoid to oblong-lanceoloid, ± terete to quadrangular, (2.2–)3.4–4.5(–5.6) × (0.8–)0.9–1.2(–1.3) mm;

distal spikelet spreading or ascending;

floral scales 1(–3), appressed, stramineous, red-spotted, strongly 3(–4)-ribbed on either side of green part, medially weakly 3-ribbed, ovate to elliptic ovate, (2.4–)2.8–3.3(–3.6) × 1.6–2 mm, apex acute, mucronulate from excurrent midrib.

Flowers

anthers (0.3–)0.4–0.6 mm;

styles 0.4–0.6(–0.8) mm;

stigmas 1–1.4 mm.

Achenes

brown, stipitate, ellipsoid, (1.6–)1.8–2 × (0.7–) 0.8–0.9 mm, stipe 0.1–0.2 × 0.2 mm, apex ± truncate, apiculate, surfaces puncticulate to glabrous.

Cyperus dentoniae

Phenology

Fruiting mid summer–fall (Jul–Sep).

Habitat

Various dry, open environments

Elevation

500–1000 m (1600–3300 ft)

Distribution

AZ; Mexico; Central America; South America

[BONAP county map]

Discussion

Cyperus dentoniae was not treated in G. Kükenthal’s monograph (1935–1936), apparently because he did not see any materials of the species. The plant has been treated as “C. asper (Liebmann) O’Neill,” a name based on Mariscus asper Liebmann and a synonym of C. mutisii (A. B. Ayers 1946).

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

Source

FNA vol. 23, p. 187.

Parent taxa

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. 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

Mariscus pubescens, C. flavomariscus var. peduncularis, C. flavus var. peduncularis

Name authority

G. C. Tucker: Syst. Bot. Monogr. 2: 56. (1983)

Web links

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

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Cyperus dentoniae

Cyperus dentoniae