Cyperus. CYPERACE^E. 213 



* Flowers all perfect : spikelets few - many-flowered, solitary or spieate, the spikes capitate or 



umbellate : only 1 or 2 of the lower scales usually empty. 

 +- Spikelets more or less flattened, the scales being in 2 ranks : inflorescence involucrate. 



CTPXEKA 



1. Cyperus. Perianth (bristles, etc.) none. Style slender, deciduous. Spikelets spicate or 



clustered. 



DULICHIUM SPATHACEUM, Pers. (the only species), distinguished by its very leafy jointed 

 stems and axillary solitary peduncles bearing sessile many-flowered spikelets, and by the linear- 

 oblong nutlet acute with the base of the long 2-cleft style and surrounded by 6 to 9 retrorsely 

 barbed bristles, occurs on the Columbia River and is common in the Atlantic States. The erect 

 terete hollow culm is nearly covered by the sheaths of the short flat linear 3-ranked leaves (the 

 lower sheaths without blades) ; spikelets in a 2-ranked spike, linear-lanceolate, the naked rha- 

 chis articulated at the base of each scale. 



t- -t- Spikelets many-flowered, not flattened, the scales imbricated all around. SCIRPE^E. 

 n- Style not dilated at base. 



2. Scirpus. Spikelets solitary or clustered, or in a compound umbel, the stem often leafy at 



base and inflorescence involucrate. Style deciduous or only the base persistent. Barbed 

 bristles present at base of the nutlet or wanting. Stamens mostly 3. Perennials. 



3. Eriophorum. As Scirpus, but the numerous naked bristles long-exserted and silky in fruit. 



Spikelets few. Stamens 1 to 3. Perennial. 



4. Hemicarpha. As Scirpus, but without bristles and with a minute hyaline bractlet between 



each flower and the rhachis. Spikelets solitary or few in a sessile apparently lateral clus- 

 ter. Stamen 1. Low annuals. 



n- -n- Style enlarged at base. 



5. Eleocharis. Spikelet solitary, terminal upon a leafless bractless stem. Base of the style 



persistent. Bristles usually present. Stamens 3. 



6. Fimbristylis. Spikelets in an involucrate umbel. Stem leafy at base. Style usually wholly 



deciduous. Bristles none. Stamens 1 to 3. Perennials. 



* * Spikelets polygamous, few-flowered, ovoid or oblong-ovoid, the scales loosely imbricate all 



around, only the terminal ones fertile. RHYNCHOSPOKE.E. 



7. Cladium. Spikelets in cyme-like panicles. Stems tall, leafy. Bristles none. Style not en- 



larged at base, deciduous. Nutlet corky at the apex. Stamens 2. Perennial. 

 RHYNCHOSPORA, Vahl, is distinguished from Cladium. by the presence of bristles and the nutlet 

 crowned by the persistent tuberculate base of the style. R. ALBA, Vahl, has been collected in 

 Oregon (Hall), a slender species with narrowly linear leaves, the lanceolate tawny spikelets in 

 a close terminal corymb ; perfect flowers 1 or 2, with 3 stamens, 9 to 12 or more bristles minutely 

 barbed downward, and a smooth oblong-obovate nutlet bearing a long flattened awl-shaped tuber- 

 cle. It is common eastward and also in Europe. 



* * * Flowers monoecious, in the same or distinct spikelets, or dioecious ; pistillate flowers en- 



closed in an inflated sac-like persistent perigynium. CARICE.S:. 



8. Carex. Spikelets solitary, spicate or paniculate. Hypogynous bristles or scales wholly 



wanting or a single short bristle at the base of the ovary. 



1. CYPERUS, Linn. GALINGALE. 



Flowers perfect, in few - many-flowered flattened or sometimes terete spikelets ; 

 the concave more or less carinate scales in 2 ranks, often decurrent upon the rhachis, 

 at length deciduous, 1 or 2 of the lowest usually sterile. Hypogynous scales or 

 bristles none. Stamens 1 to 3. Style not thickened at base, 2 - 3-cleft, deciduous. 

 Nutlet lenticular or triangular, not beaked, smooth or nearly so. Perennials or 

 annuals, with mostly triangular and nearly naked simple stems, sheathed at base by 

 the nearly radical leaves ; inflorescence subtended by a mostly conspicuous foliaceous 

 involucre, usually irregularly umbellate with unequal rays, the spikelets in spikes 

 solitary or clustered upon the rays, the central spike or cluster always sessile, and 

 the whole often contracted into a single more or less dense head. 



A very large genus, numbering 500 species or more, especially abundant in tropical and sub- 

 tropical regions. About 50 species are found within the limits of the United States. Most of the 

 following sections have been by some authorities regarded as distinct genera. 



