S8 TRIANDRIA. MONOGYNIA. 



tropics; one, the F. wnbellata, is also coftimon to India; lite 

 4th species, F. caiiescensy is a native of Africa. 



68. CENCHRUS. (Bur-grass.) 



Involucrum\?iC\\\mief echinate, 3 to 4-flower- 

 ed. Calix S-valved, S-flowered, 1 fertile the 

 other sterile. Style bifid, (sometimes 2.) 



Culm round, in some species branched; flowers in- 

 spikes or racemes; proper involucrum caliciform, spiny or 

 hispid, sometimes roundish with a laciniate margin, in 

 other species setiform, or more or less deeply divided. 



Species. 1. C. echinatus. 2. fribidoides. 



Of this genus there is 1 species in India, but doubtful 

 as a Cenchnis, 3 in Barbary, besides the C. echinattis equal- 

 ly indigenous to the United States; the C. capitaiits of 

 Barbary, exists also in France and Italy, and the C. hor- 

 deiformis is found also in Asia. There is another species in 

 Babao, one of the Friendly islands; another in Montevideo 

 in South America; 2 others at the Cape of Good Hope; 

 and lastly, a shriibbi/ species in the mountains of Ar- 

 menia. 



This genus is very nearly allied to Pennisetum. 



59. LIMNETIS. Richard. Trachynotia. M- 

 chaux, Spartina. Schreber. (Marsh-grass.) 

 Flowers in unilateral spikes almost imbri- 

 cated in 2 rows. — Calix 2-valved, carinate, and 

 conipressed; one of the valves much smaller 

 than the other. Corolla 2-vaIved, awnless. Styles 

 long, 1 or 2, Ferisporium 0. Seed cona- 

 pressed. 



Culm round, rarely hollow, often tall, ([.he JL. pofi^sta- 

 chya from 3 to lO feet high); leaves large and long; spikes 

 in a simple appressed or expanding panicle, long, and 

 many-flowered; valves of the calix very unequal, the larger 

 valve acutely carinate; the carina almost aculeate or 

 sharply ciliate. Seed compressed, oblong. 



Notwiilistandirg the great disparity of habit, this ge- 

 nus is very nearly allied to the Daciylis, at least to the D. 

 glomerata, which occurs sometimes 1-flowered. 



Species. 1. Z.jw??cea. 2. cynosiiroides. S polifstacht/a.4. 

 glabra. Tliis last species grows up the Missouri as far as 

 the great Northern Bend, around Fort Mandan. The ge- 

 ^us LimJietis, w^th the exception of the f^. piingens of 



