CYPERACEiE. 399 



IV. Hypolytre^. Flowers perfect. Scales of the spikes imbri- 

 cate on all sides, each 1-floiverecl ; the flowers with a 1 — 4-valved (not 

 bristle-form) perygynium. 



12. HEMICARPHA. iVees.— Hemicarpha. 



(From the Greek rjjxisvs, half, and Kapcpo;, straw ; the flowers having a valve 

 only on one side.) 



Spikes ovoid. Scales very numerous, deciduous. Flowers 

 with a single valve, which is opposite the scale. Stamen 1. 

 Style 2 -cleft. Achenium oblong. 



H. subsquarrosa Nees: culm setaceous, compressedj sulcate; involucre 

 2-leaved, long, unequal ; spikes 2 — 3, ovoid, sessile, lateral ; scales rhombic- 

 obovate, with a short mucronate recurved point ; achenium obovate-oblong, 

 somewhat compressed. ( To?r. N. Y. Ft.) Scirpus subsquarrosus M^M. 



Sandy shores. N. Y. to Geor. July. 0. — Culms about 2 inches high, in 

 dense tufts, leafy at base. Leaves setaceous. Spikes sometimes solitary. 

 Scales very numerous. Dwarf Hemicarpha. 



V. CLADEiE. Flowers perfect, rarely diclinous. Spikelets 1 — 3- 

 flowered. Scales imbricate in a somewhat three or four-rowed order ; ' 

 the lowest empty. Perigynium none. Stamens 2 — 12. Styles 2 — 3- 

 cleft. Achenium smooth or irregularly wrinkled. 



13. CLADIUM. Browne.— Tviig Rush. 

 (From the Greek KKaioi, a twig ; but the application is not understood.) 



Spikelets 1 — 2-flowered. Scales few, imbricate in a some- 

 what trifarious manner ; the lowest empty. Bristles none. 

 Stamens mostly 2. Style 2 — 3-cleft. Achenium globose-ovoid. 



C. mariscoides Torr.: culm obscurely triangular; cymes compound, 

 2 — 4-rayed, nearly naked, the rays elongated ; spikelets in heads of 3—8 

 to<rether ; style 3-clefl. Schcemis mariscoides Miihl. 



Bogs and ponds. Can. to Del. July. %. — CmZtti 2 feet high, nearly smooth. 

 Leaves channelled, with a long compressed point, nearly smooth on the margin. 

 Scales about 6, brown ; 4 lower ones usually empty. Smooth Twig Rush. 



VI. Hhynchospore^. Flowers perfect or polygamous. Spikelets 

 mostly few-flowered. Scales irregularly imbricate, obscurely two- or 

 three-rowed. Perigynium of several rough or plumose bristles, rarely 

 wanting. Achenium beaked. 



14. RHYNCHOSPORA. F«AZ.— Beak Rush. 



(From the Greek p'<^yx°^) a. leak, and anopa, a seed.) 



Spikelets few-flowered. Scales loosely imbricate ; the lower 

 ones smaller and empty. Bristles 6, rarely 10 — 12. Stamens 



