TRIANDKIA. DIGTNIA. 57 



Species. 1. P. setaceum. 2. debile. 3 ciUatifolivm. 4- 

 dasyphyUiim, Kl. 5 pracox. 6 ^<rT»e. 7 ■ Floridannm. S. pU- 

 eatuhim. 9. pu}pnrasce7is, E 10. (Ustichum. 11. vaginatum. — 

 $11. Spikes in racemes.— 12 membranaceum. Vo. stohnife' 

 rum. In New- Jersey, P?/7'sA. Near New Orleans abundant. 

 I suspect these 2 last marked as ^5pecies, are varieties of 

 the same plant. This species, oritrinally discovered in 

 Peru, has been greatly recommended to agriculturists. 

 In warm, maritime situations, it continues growing and 

 flowering throughout the year, and is undoubtedly pro- 

 ductive and important in South America; but in Europe 

 it is entirely destroyed by the earliest frosts of the au- 

 tumn, being quite a tropical annual 



This genus, with the exception of the above species, iB 

 confined to the West ladies and the tropical portions of 

 the American continent; there is at the same time, 1 spe- 

 cies in Japan, 2 in India, 1 in Surinam (Africa), and ano- 

 ther in China The P. conjugatum is common both to Ja- 

 maica and Surinam. There are also a few species in 

 New Holland. Europe produces no species of this ge^ 

 nus. 



85. ARISTIDA. L. 



Ca^ix2-Talved,l -flowered. Corolla 1-valved, 

 terminated by 3 awns. 



Culm paniculate; panicle sometimes contracted like a 

 dense spike, or elongnted into a compound raceme, in 

 others spreading or divaricate, in some species tricho- 

 tomous, in others dichotomous. Flowers commonly 

 approximating by pairs; calix as in Avena and Stipa, 

 longer or shorter than the corolla. Corolla generally de- 

 scribed as consisting of a single glume; Mr. Elliott de- 

 tects the rudiments of a minute inner glume in Jl. spici- 

 formis and .^ latiosa. The corolla of all the species is 

 terminated by 3 awns, sometimes of very unequal length, 

 scabrous or plumose, inclined in various directions, the 

 central awn often horizontal, sometimes all equal and 

 then divaricate, the awns very rarely contorted. 



Species. 1. A-spiciformis, El. 2. stricta. 3. lanoso, El. 

 4. gracilis, E. 5. oUgantha. 6. dichoComa, (the larger con- 

 torted awn of this species is hygrometric.) 7. paikinsy (in 

 depressed situations, near Fort Mandan on the Missouri.) 



8. * tuberculosa. Culm rigidly erecl, dichotomous, with 

 tumid articulations and small tubercles or callosities in 

 the axillae of all the branches; panicle rigid, rather short, 

 ramuli approximating towards the summit of the culm, 



