504 CYPERACEJE. (SEDGE FAMILY.) 



shaped persistent style, and somewhat margined ; culm 4'- 9' high : leaves flat. 

 (D — Inundated places, Rhode Island and Plymouth, Massachusetts. July. 



11. DICHBOMEMA, Richard. Dichromena. 



Spikes terete, flattened, aggregated in a terminal leafy involucrate head, 

 many-flowered; some of the flowers imperfect. Perianth none. Stamens 3. 

 Style 2-cleft. Achenium lenticular, wrinkled transversely, crowned with the 

 broad tubercled base of the style. — Culms leafy, from creeping rootstocks ; the 

 leaves of the involucre mostly white at the base (whence the name, from bis, 

 double, and xP&pa, color). 



1. I>. Icncoccpliala, Michx. Culm triangular ; leaves narrow ; invo- 

 lucre 5-7-leaved; achenium truncate, not margined. 1J. — Damp pine barrens 

 of New Jersey to Virginia and southward. August. 



12. CEBATOSCHflENUS, Nees. Horned Rush. 



Spikes spindle-shaped, producing 1 perfect and 1 to 4 staminate flowers. 

 Scales few and loosely imbricated ; the lower ones empty. Perianth of 5 - 6 

 rigid or cartilaginous flattened bristles, which arc somewhat dilated or united 

 at the base. Stamens 3. Style simple, entirely hardening in fruit into a long 

 and slender awl-shaped upwardly roughened beak with a narrow base, much ex- 

 serted, and several times longer than the flat and smooth obovate achenium. — 

 Perennials, with triangular leafy culms, and large spikes clustered in simple or 

 compound terminal and axillary cymes. (Name composed of Kepas, a horn, and 

 axoivosi a rush.) 



1. C comic ulata, Nees. Cymes decompound, diffuse ; bristles aid-shaped, 

 stout, unequal, shorter than the achenium. — Wet places, Penn. to Illinois, and 

 southward. August. — Culm 3° -6° high. Leaves £' wide. Fruit with the 

 taper beak 1' long. 



2. C macrostacfaya, Gray. Cymes somewhat simple, small, the spikes 

 closely clustered ; bristles capillary, twice the length of the achenium. — Borders of 

 ponds, E. Massachusetts, Rhode Island, New Jersey, and rare southward. 

 (Some states occur intermediate between this and the last.) 



13. BHYNCHOSPOBA, Vahl. Beak-Rush. 



Spikes ovate, few - several-flowered ; the lower of the loosely imbricated 

 scales empty, the uppermost usually with imperfect flowers. Perianth of 6 (oi 

 rarely more) bristles. Stamens mostly 3. Style 2-cleft. Achenium lenticular 

 or globular, crowned with the dilated and persistent base of the style (tubercle). 

 — Perennials, with more or less triangular and leafy culms ; the small spikes in 

 terminal and axillary clusters, cymes, or heads : flowering in summer. (Name 

 composed of pvy^os. a snout, and <nropd, a seed, from the beaked achenium.) 

 * Achenium transversely wrinkled, more or less flattened, bristles upwardly denticulate. 



1. K. cymosa, Nutt. Culm triangular; leaves linear (£' wide); cymes 

 corymbose ; the spikes crowded and clustered; achenium round-obovate, twice the 



