74 Cyperaceae 
F. Basal leaves 1.5——3 dm. long, flexuous. E. 
S. longifolium 5m. 
FF. Basal leaves 0.5——1 dm. long: W.C. Ex GS. basalitcotasrs- latifolium; 
S. rigidum; S. glabrum.) 
S. brevifolium 5™. 
CYPERACEAE _ Sedge Family 
Herbs, annual or perennial; rhizomes present; stems 3-angled or terete, mostly 
solid. Leaves attenuate, mostly basal; sheaths not split. Flowers in spilees or spikelets, 
small, perfect or monoicous or dioicous, in the axils of scales; scales imbricate, chaffy; 
spikes again variously grouped unless solitary. Perianth none or of mere bristles or 
scales. Stamens usually 2-3, hypogynous; anthers basifixed. Ovary 1-celled; ovule 
1; style 2—3-cleft. Fruit an akene, lens-shaped or somewhat 3-angled, membranous or 
crustaceous or bony. 
A. Akenes not enclosed in a sac-like structure; flowers perfect; spikelets all alike. 
B. Spikelets more or less flat; scales in 2 opposite rows. 
C.~ Stem nearly naked; leaves mostly basal; perianth none. CYPERUS (p. 75) 
CC. Stem with 3 distinct rows of leaves; leaves mostly on the stem; perianth of 
6—9 bristles. DuLICHIUM (p. 75) 
“BB. Spikelets terete; scales imbricated all around. 
D. Akenes not crowned by the bulbous base of the style. 
E. Spikelets not a cottony mass. 
F. Perennial; perianth of 0—6 bristles. Scirpus (p. 76) 
FF. Annual; perianth of a single hyaline scale between the rachilla and the 
akene. HEMICARPHA (p. 74) 
EE. ‘Spikelets each a white to brown cottony head of hairs |—3 cm. wide. 
ERIOPHORUM (p. 75 
DD. Akenes crowned with the persistent bulbous base of the style. 
G. Stem leafless; spikelets solitary, terminal; perianth-bristles usually present, 
On 123 ELEocHaArRis (p. 77) 
GG. Stem leafy at least at base; spikelets more than 1, in an involucrate umbel. 
H. Akene 3-angled; perianth-bristles none. STENOPHYLLUM (p. 78) 
HH. Akene lens-shaped; perianth-bristles 9—15, downwardly barbed. 
RHYNCHOSPORA (p. 78) 
AA. Akenes enclosed in a sac-like structure; flowers monoicous; spikes mostly of 2 
kinds. CAREX (p. 78) 
HEMICARPHA HEMICARPHA 
Low, tufted, mostly annual; stems erect or spreading, almost filiform. Leaves al- 
most filiferm. Spikelets terete, small, terminal, solitary or in a head-like cluster; involucre 
|—3-leaved; scales spirally imbricate all around, deciduous, all with perfect flowers in 
their axils, with | hyaline bract on inner face. Perianth-bristles none. Stamens 1—3. 
Style 2-cleft, deciduous, not swollen at base. Akene oblong, turgid or lens-shaped. 
Ours in moist sandy soil. (Gk. hemi—half, karphos=chaff; because this genus has 
only | inner scale while most related genera have 2 or more.) 
A. Scales spreading, 2—3 times as long as the akenes. 
B. Scales broadly ovate, with long-acuminate spreading tip; akene brown. C-. 
H. occidentalis Gray 
BB. Scales oblong-ovate or obovate, with short-acuminate tip; akene black. E. 
(H. intermedia.) H, aristulata Nels. 

