The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

one-flower flatsedge

fragrant flatsedge, rusty flat sedge, scented sedge

Habit Herbs, perennial, cespitose, rhizomatous. Herbs, annual (or short-lived perennial).
Culms

trigonous, basally tuberous-thickened, (5–)15–40(–80) cm × 1–2.5 mm, glabrous.

trigonous, (4–)10–50(–130) cm × (0.5–)1–4 mm.

Leaves

flat to V-shaped, (5–)10–30(–60) cm × (0.5–)1–3(–4) mm.

flanged V- or inversely W-shaped, 5–30(–60) cm × 4–12 mm.

Inflorescences

spike 1, loosely to densely ovoid to cylindric, 8–36 × 8–20 mm;

rays 3–6(–9), (5–)10–32 cm;

bracts 3–6, horizontal to ascending at 30°, V-shaped, (1–)3–15(–30) cm × 0.5–4.5 mm;

rachilla deciduous, wings 0.5–0.7 mm wide.

spikes 1–5(–12), loosely to densely cylindric, ovoid, or ± pyramidal, 10–20(–40) × (8–)10–30(–35) mm;

rays (0–2)6–9(–12), 2–8(–13) cm;

if rays absent, infloresence a single dense, capitate cluster of closely imbricate spikes;

bracts (4–)5–8(–10), horizontal to ascending at 30–60°, (3–)10–25(–55) cm × 1–14 mm;

rachilla hyaline or thickened bronze, carmine, or yellowish, wings clasping achene.

Spikelets

(5–)20–35(–65), linear to oblong (without narrowed basal portion), quadrangular; (2.2–)4–10(–18) × 0.7–1.1 mm;

floral scales persistent, 1–5, appressed, pale greenish white laterally, stramineous with reddish dots, or deep red, greenish or light brown medially, 3–6-ribbed laterally, narrowly ovate to oblong-elliptic, 2.6–3.9 × 1.6–2 mm, apex rounded to ± acute, entire, mucronulate;

distal scale with glabrous midrib and mucro 0.1–0.3(–0.5) mm;

sterile terminal scale of spikelet only 0.4–0.6 mm wide, involute, frequently uncinate.

(10–)20–60(–100), linear-oblong to narrowly linear, cylindric to slightly flattened (when scale tips spreading), (5–)8–15(–38) × 0.8–1.3(–1.9) mm;

floral scales (4–)8–12–(30), medially green, laterally reddish to stramineous to shiny brown or beige, medially 2–5-ribbed, laterally 1–3-ribbed, ovate to elliptic, (2–)2.2–2.8(–3.2) × (1.2–)1.4–1.6(–1.8) mm, apex entire or emarginate with mucro to 0.3 mm.

Flowers

anthers (0.3–)0.4–0.6 mm;

styles 0.4–0.5 mm;

stigmas 0.5–0.9 mm.

anthers (0.2–)0.3–0.4(–0.7) mm;

styles 0.4–0.7(–1) mm;

stigmas (1–)1.5–3 mm.

Achenes

light brown to reddish brown, sessile or slightly stipitate, ellipsoid, (1.8–)2–2.4 × 0.6–0.8(–0.9) mm, apex slightly apiculate, surfaces puncticulate.

brown, reddish brown, or black, stipitate, narrowly ellipsoid to oblong (rarely obovoid-oblong), (1–)1.2–1.5(–1.9) × 0.5–0.6(–0.75) mm, stipe 0.1–0.2 mm, apex acute to barely obtuse, surfaces finely papillose.

Cyperus retroflexus

Cyperus odoratus

Phenology Fruiting mid summer–early fall (Jul–Sep). Fruiting summer–early fall.
Habitat Damp, disturbed soils, croplands Emergent shorelines, disturbed, muddy places, fresh or slightly brackish marshes
Elevation 0–1000 m (0–3300 ft) 0–1500 m (0–4900 ft)
Distribution
from FNA
AL; AR; AZ; MO; MS; NM; OK; TX; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WA; WI; WV; HI; ON; QC; Central America; South America; Asia; Africa; Australia
[WildflowerSearch map]
[BONAP county map]
Discussion

Cyperus retroflexus is distinguished from other species of Cyperus with deciduous spikelets by the involute, sterile terminal scale of the spikelet. In plants with cuspidate scales, the terminal scale is usually somewhat recurved, giving the appearance of a hook at the end of the spikelet.

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

As circumscribed here, Cyperus odoratus is easily identified by its cylindric to subcylindric spikelets in which the corky rachilla of the mature spikelet disarticulates at the base of each scale. The mature spikelet breaks into segments each consisting of a scale and an internode of the rachilla clasping the achene with its corky wings. Cyperus odoratus is an exceedingly variable pantropical and warm-temperate species. Numerous segregates have been named, some of which may deserve recognition when the species is studied in detail worldwide.

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

Source FNA vol. 23. FNA vol. 23, p. 191.
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. 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. 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. 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 var. retroflexus, Mariscus uniflorus C. acicularis, C. californicus, C. eggersii, C. engelmannii, C. ferax, C. ferax subsp. engelmannii, C. ferax subsp. speciosus, C. ferruginescens, C. haenkei, C. huarmensis, C. macrocephalus, C. michauxianus, C. odoratus var. engelmannii, C. oxycarioides, C. speciosus, C. squarrosus var. parvus, Diclidium aciculare, Diclidium odoratum, Mariscus ferax, Mariscus huarmensis, Torulinium eggersii, Torulinium ferax, Torulinium macrocephalum, Torulinium michauxianum, Torulinium odoratum
Name authority Buckley: Proc. Acad. Nat. Sci. Philadelphia. 14: 9. (1862) Linnaeus: Sp. Pl. 1: 46. (1753)
Web links