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

haspan flatsedge

nut flatsedge, nut grass, yellow nut sedge, yellow nut-grass

Habit Herbs, perennial, cespitose, shortly rhizomatous. Herbs, perennial, stoloniferous; stolons soft, spongy, flexible when dried, 2–8(–15) cm, bearing tubers (3–)6–11 mm diam.
Culms

trigonous, (2–)25–60(–100) cm × 1–4 mm, soft (flattened in drying), glabrous.

trigonous, 15–60 (–100) cm × 0.6–3.4 mm, glabrous.

Leaves

usually reduced to sheaths, occasionally with blades, flat to V-shaped, (3–)10–30 cm × (1–)2.5–5 mm.

3–7, flat to V-shaped or flanged V-shaped, (6–)20–40(–80) cm × 2–4 (–6.5) mm.

Inflorescences

heads loosely digitate;

rays (5–)10–12(–15), 1–15(–20) cm; 2d order rays usually present, (1–)6–12(–25) mm; 3d order rays sometimes present, 1–6 mm;

bracts 2(–3), horizontal to ascending at 30–60°, longer (3–)6–18 cm × 2–4 mm, shorter (0.5–)2.5–6.5 cm × 1–2(–3) mm.

spikes broadly ellipsoid to ovoid or hemispheric, (12–)18–30 × (12–)18–35 mm;

rachis 4–17 mm;

rays 4–10, (0.3–)2–12 cm;

bracts (3–)4–5(–7), ± horizontal to ascending at 45(–75)°, V-shaped to flanged V-shaped, (1.5–)5–30 cm × 0.5–4 mm;

rachilla persistent, wings hyaline, 0.3–0.5 mm wide.

Spikelets

1–15, linear-lanceoloid, ± compressed-quadrangular, 3–18 × 1–1.6 mm;

floral scales 10–20(–40), laterally reddish to greenish brown, dull, often clear-edged, medially greenish, laterally 1-ribbed, medially 1-ribbed, oblong to obovate, 1–1.5(–1.9) × 0.8–1 mm, apex mucronate, glabrous except for cluster of crystalline prickles at apex.

(3–)10–20(–28), divaricate or ascending, yellowish brown to dark brown, linear to linear-lanceoloid, compressed-quadrangular, (5–)10–20(–55) × (1.2–)1.4–2(–3) mm;

floral scales persistent, 6–34, spreading or appressed, ovate-lanceolate, laterally 7–9-ribbed, laterally yellowish brown to dark brown medially brownish, reddish, or greenish, ovate, or ovate-deltate, medially 3-ribbed, 1.8–2.7(–3.4) × (1–)1.5–1.8(–2.4) mm, apex acute or subacute.

Flowers

stamens 3;

anthers 0.3–0.5 mm;

styles 0.4–0.9 mm;

stigmas 0.5–0.8(–1.3) mm.

anthers (1–)1.2–1.5(–2.1) mm;

styles (0.7–)1–1.2(–2.2) mm;

stigmas (1.2–)1.8–2.3(–4) mm.

Achenes

white or reddish brown, stipitate, globose to obovoid or ellipsoid, 0.5–0.6(–0.7) × 0.3–0.4(–0.5) mm, base nearly cuneate, stipe 0.1 × 0.1–0.2 mm, apex obtuse to acute, apiculate or entire, surfaces granular to papillose.

(seldom maturing) brown, sessile, ellipsoid, (1.1–)1.3–1.5(–1.6) × 0.3–0.6(–0.8) mm, apex obtuse, surfaces puncticulate.

Cyperus haspan

Cyperus esculentus

Phenology Fruiting summer.
Habitat Swales between dunes, marshes, pond shores
Elevation 0–200 m (0–700 ft)
Distribution
from FNA
AL; FL; GA; LA; MS; NC; SC; TX; VA; Mexico; Central America; South America; Asia; Africa; Australia
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; BC; NB; ON; QC; nearly worldwide
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 4 (3 in the flora).

Cyperus esculentus is a widespread and polymorphic species. Although seven varieties have been recognized (G. Kükenthal (1935–1936), recent studies based primarily on spikelet features provided support for four varieties (P. Schippers et al. 1995). Cyperus esculentus var. esculentus is restricted to the Old World.

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

Key
1. Spikelets ascending-erect; floral scales deltate-ovate, widest ca. 1/4–1/3 of length.
var. heermannii
1. Spikelets divaricate; floral scales ovate to ovate-lanceolate, widest at midlength.
→ 2
2. Spikelets (1.2–)1.5–2 mm wide; floral scales 1.8–2.7 mm; anthers (1–)1.3(–1.6) mm; styles (0.7–)1–1.2 mm; stigmas (1.2–)1.8(–2.5) mm.
var. leptostachyus
2. Spikelets 2.4–3 mm wide; floral scales (2.7–) 2.9–3.4(–3.6)mm; anthers (1.2–)1.3–2(–2.1) mm; styles (0.9–)1.3–2(–2.2) mm; stigmas (2–) 2.3–2.8(–4) mm.
var. macrostachyus
Source FNA vol. 23, p. 151. FNA vol. 23.
Parent taxa Cyperaceae > Cyperus > subg. Pycnostachys 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. 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. 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
Subordinate taxa
C. esculentus var. heermannii, C. esculentus var. leptostachyus, C. esculentus var. macrostachyus
Synonyms C. autumnalis, C. haspan subsp. juncoides, C. haspan var. americanus, C. juncoides
Name authority Linnaeus: Sp. Pl. 1: 45. (1753) Linnaeus: Sp. Pl. 1: 45. (1753)
Web links