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mosquito flatsedge

granite flatsedge

Habit Herbs, perennial; rhizomes 3–20 cm × 1–2 cm, indurate. Herbs, annual, cespitose, with roots fibrous.
Culms

stoutly trigonous, thickened, 50–300 cm × 5–30 mm, basally indurate, glabrous.

trigonous, glabrous.

Leaves

V-shaped, with cross ribs, 40–130 cm × 10–15 mm, margins and keel scabrid.

V-shaped to flat, (2–)4–11 cm × 3–4 mm.

Inflorescences

spikes appressed-ascending, narrowly cylindric, (2–)3–45 mm × (4–)7–10 mm;

rays (5–)9–12, 2–22(–30) cm; 2d order rays distinctly flattened, 1–10 cm; 3d order rays flattened, 0.5–3 cm;

rachis 2.5–4 cm;

bracts (6–)9–10, ascending at 45–75°, V- or inversely W-shaped, (5–)15–90 cm × 0.5–20 mm;

rachilla persistent, wings 0.2–0.4 mm wide.

rays absent;

bracts 2–4, ± horizontal, flat, 1–6.5 cm × 2–3 mm;

rachilla persistent, wingless.

Spikelets

(4–)10–35, appressed-ascending, compressed, linear, 7–12(–15) × 0.6–1.2 mm;

floral scales deciduous, 6–20, marginally clear, laterally brown, medially green, laterally 2–3-ribbed, medially 1-ribbed, oblong-ovate, (3.2–) 3.8–4.3 × 1.2–1.7 mm, apex spreading, acute to obtuse, mucronulate.

10–40, compressed, ovoid to linear-lanceoloid, quadrangular, 5–9 × 2–3 mm;

floral scales deciduous, 5–20, spreading, pale greenish to reddish brown, laterally (5–)7–9(–13)-ribbed, ovate, 3–4 × 1–2 mm, apex straight, excurved mucronate, or cuspidate.

Flowers

anthers 0.7–0.9 mm, connective apex bright red, oblong, to 0.1 mm;

styles 0.8–1.3 mm;

stigmas 2–3.3 mm.

stamens 1–2;

filaments 1.5 mm;

anthers 0.8–1 mm, connective apex reddish yellow, less than 0.1 mm;

styles 0.8–1 mm;

stigmas 1–1.2 mm.

Achenes

brown, sessile, narrowly ellipsoid, 1.8–2.5 × 0.8–1.3 mm, apex ± acute, not apiculate, surfaces puncticulate.

brown to reddish brown, broadly ellipsoid to obovoid, 0.8–1.2 × 0.5–0.6 mm, base ± cuneate, apex truncate-obtuse, surfaces puncticulate.

Cyperus prolixus

Cyperus granitophilus

Phenology Fruiting summer. Fruiting summer.
Habitat Coastal marshes Thin soil over outcrops of granite or sandstone of the Piedmont and inner coastal plain
Elevation 0–10 m [0–30 ft] 50–400 m [160–1300 ft]
Distribution
from FNA
LA; Mexico; Central America; South America
[BONAP county map]
from FNA
AL; GA; NC; SC; TN; VA
[WildflowerSearch map]
[BONAP county map]
Discussion

Cyperus prolixus produces large plants, similar in habit to C. giganteus and C. papyrus but easily distinguished by flattened rays.

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

Cyperus granitophilus is documented as an autotetraploid derivative of C. squarrosus (L. W. Garoni and W. H. Murdy 1964).

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

Source FNA vol. 23, p. 167. FNA vol. 23, p. 165.
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. 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. 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. amplissimus
Name authority Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 206. (1816) McVaugh: Castanea 2: 103, figs. 4–8. (1937)
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