20. Cyperus Hallii Britton. Hall's Cyperus. •

Fig. 740

C. Hallii Britton, Bull. Torr. Club 13: 211. 1886.

Perennial by scaly rootstocks, culm rather stout, 2°-3° tall, about equalled by the leaves. Basal leaves 2"-3" wide; involucral leaves 3-6, the longer very much exceeding the inflorescence; umbel compound, its longer rays 3'~4' long, the raylets sometimes 1' long; spikelets numerous, loosely clustered, linear, 7 - 15-flowered, s"-8" long, 1"- 11 /2" wide; involucels setaceous; scales ovate, acute, strongly 7-9-nerved, dark reddish-brown or with lighter margins, their tips not appressed; stamens 3; style 3-cleft, its branches much exserted; achene linear-oblong, 3-angled, about one-half as long as the scale.

Kansas and Oklahoma to Texas. July-Sept.

21. Cyperus Esculentus L. Yellow Nut-Grass

Fig. 741

Cyperus esculentus L. Sp. PI. 45. 1753. Cyperus phymatodes Muhl. Gram. 23. 1817. Cyperus esculentus angustispicatus Britton, Bull. Torr. Club 13: 211. 1886.

Perennial by scaly horizontal tuber-bearing root-stocks, culms usually stout, 1°-2 1/2° tall, commonly shorter than the leaves. Leaves light green, 2"-4"' wide, the midvein prominent; those of the involucre 2,-6, the longer much exceeding the inflorescence; umbel 4-10-rayed, often compound; spikelets numerous in loose spikes, straw-color or yellowish-brown, flat, spreading, 6"-12" long, 6"-12" wide, many-flowered; scales ovate-oblong, subacute, 3-5-nerved; rachis narrowly winged; stamens 3; style3-cleft; achene obovoid, obtuse, 3-angled.

In moist fields, New Brunswick to Minnesota, Nebraska, Florida and Texas. Also on the Pacific Coast from California to Alaska, in tropical America, and widely distributed in the Old World. Sometimes a troublesome weed. The species consists of numerous races, differing in length and width of spikelets. Edible galingale. Earth-almond. Rush-nut. Aug.-Oct.

22. Cyperus Erythrorhizos Muhl. Red-Rooted Cyperus

Fig. 742

Cyperus erythrorhizos Muhl. Gram. 20. 1817.

Annual, culms tufted, stout or slender, 3-2 tall. Leaves 1 1/2"-4" wide, rough-margined, the lower longer than or equalling the culm, those of the involucre 3-7, some of them 3-5 times as long as the inflorescence; umbel mostly compound, several-rayed; spikelets linear, subacute, 3"-10" long, less than 1" wide, compressed, many-flowered, clustered in oblong, nearly or quite sessile spikes; scales bright chestnut brown, oblong-lanceolate, mucronulate, appressed, separating from the rachis at maturity, the membranous wings of the rachis separating as a pair of hyaline interior scales; stamens 3; style 3-cleft; achene sharply 3-angled, oblong, pointed at both ends, pale, one-half as long as the scale.

In wet soil, especially along streams, southern Ontario to Massachusetts, Florida, Minnesota, Kansas, Texas and California. Aug.-Oct.