52 1 ' VIM K\< I 1 . (SKIXiE FAMILY.) 



of the Btyk ftubercled). Perenniala, with jointed and leafy culms. Spikes 

 small, disposed in axillary and terminal corymbs or clusters. 



§ 1. FKIOCII.1. II'.. Bristles of the perianth 6, plumose. 



1. R. plumosa, Ell. Culms (6'-12' high.) and leaves filiform; spikes 

 few, in about three small clusters al the summit of the culm ; nut nearly globu- 

 lar, Btrongly wrinkled, pointed with the short ovate smooth tubercle ; 1 u-i- 1 l«s 

 rather longer than the nut, plumose throughout or marly to the summit. — Low 

 pine barrens, Florida to North Carolina. June ami July. 



Yar intermedia. Culms taller (l°-2° high); leaves narrowly linear; 

 clusters 4-6, forming an interrupted spike at the summit of the culm ; nut obo- 

 vate, pointed with the conical-beaked pubescent tubercle; bristles plumose only 

 at the base, or below the middle. — Sandy pine ban-ens, often dry places, Florida. 



2. R. semiplumosa, Cray. Culms erect, rigid (l°-2° high); leaves 

 narrowly linear ; spikes oblong-ovate, dark brown, crowded in a terminal head, 

 or rarely in a remote axillary one ; nut globose-obovate, faintly wrinkled, pointed 

 with the short broadly conical smooth tubercle; bristles exceeding the tubercle, 

 plumose below the middle, — Dry sandy ridges, near the coast, West Florida. 

 July and Aug. — The leaves, like those of the preceding species, have a joint- 

 like contraction near the middle. 



3. R. oligailtha, Gray. Culms (6'- 12' high) and smooth leaves bristle- 

 like, reclining ; corymb terminal, of 3-6 large (4" long) ovate-lanceolate whitish 

 stalked spikes ; nut oval, lenticular, faintly wrinkled ; tubercle dilated at the base, 

 conical, flat ; bristles longer or shorter than the nut, plumose below the middle. 



— Low open pine barrens, Florida to North Carolina. June and .July. 



§ 2. PIIYXCIIOSPORA Proper. Bristles of the perianth 3-20, smooth, 



scabrotis, or hispid. 



* Nut transverse!)/ zvrinkled or uneven: brisll,* denticulate or hispid upward. 



■*- Bristles shorter than the nut. 



4. R. rariflora, Ell. Culms and leaves bristle-form; corymbs 2-3, rc- 

 mote, spreading ; spikes few ami scattered, ovate ; nut broadly obovate, bicon- 



Btrongly wrinkled, twice as long as the 6 fragile hristles; tubercle (hit, 



broadly conical, J as long as the nut. — Low grassy pine barrens, Florida to 

 North Carolina. June and July. — Culms 1°-1|° long, commonly reclining. 

 Spike pedicelled. 



5. R. Torreyana, Cray. Culms erect, slender, nearly terete ; leaves nap- 



linear or bristle-form ; corymbs 1 -3, remote, erect ; Qui obovate, flat, about 



the 6 bristles ; tubercle compressed-conical, dilated at the base, 



\ the length of the nut — Wei ground, South Carolina, and northward. July. 



— Culm 1° - 3° high. Corymbs many-flowered and Bomewhat spreading, or 

 few-flowered and capitate. 



■ R. cymc-sa, Nutt Culms (•_>°-3 p high) 8-angledj leaves narrowly 



linear; corymb- mostly 8, distant, open or contracted ; Bpikes ovate, clustered, 



light brown; scales mucronate; nut broadly obovate, biconvex', faintly wrinkled, 



the 3-c bristles; tubercle broadlj conical, compressed, \u 



