174 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



bearing at the base a tuft of long hairs, bifid at the apex, the mid- 

 nerve extending as a short awn. 



Our species is a low, tufted perennial, with capillary blades and 

 slender solitary spikes, the spikelets somewhat distant. Species about 

 nine, East Indian and African except one American. 



Type species: Tripogon bromoifles Roth. 

 Tripogon Roth; Roem. and Schult, Syst. Veg. 2: 

 600. 1817. Only one species described. 



The American species, Tripogon spica- 

 tus (Xees) Ekman (Leptochloa spicata 

 Scribn.) (fig. 102), is found on sterile hills 

 in Texas and northern Mexico, Cuba, 

 and South America. It is of no im- 

 portance agriculturally. 



84. ELEUSINE Gaertn. 



Spikelets few to several flowered, 

 compressed, sessile and closely im- 

 bricate, in two rows along one side 

 of a rather broad rachis, the latter 

 not prolonged beyond the spikelets; 

 rachilla disarticulating above the 



FIG. 102. Tripogon spicatus. Plant, x i ; spikelet and floret, X 5. 



glumes and between the florets, glumes unequal, rather broad, acute 3 

 1-nerved, shorter than the first lemma ; lemmas acute, with 3 strong 

 green nerves close together forming a keel, the uppermost somewhat 

 reduced ; seed dark brown, roughened by fine ridges, loosely inclosed 

 in the thin pericarp. 



Annual grasses, with two to several rather stout spikes, digitate 

 at the summit of the culms, sometimes with one or two a short dis- 



