122 ME. G. BBNTHAM ON GBAMINE^. 



glumes close under the flowering one besides the two lower per- 

 sistent ones. 



52. "Uniola, Linn. (Trisiola, Eafln., Ohasmanthium, Link), 

 has four genuine North-American species, tall plants somewhat 

 variable in inflorescence, but all with flat broad spikelets in which 

 the three to sis lower glumes are empty, but in size and shape 

 pass gradually into the flowering ones, which vary from three to 

 about twenty. If U. racemiflora, Trin. (Z7. virgata, Grriseb.), from 

 the "West Indies, be retained in the genus as having flat spikelets 

 with more than two empty glumes below the flowering one, it 

 must be considered as a very exceptional species with the inflo- 

 rescence nearly oi LeptoMoa among Chlorideae. The small spike- 

 lets are closely sessile in two rows in unilateral spikes ; and these 

 spikes, shorter than in Leptochloa, are very numerous and crowded 

 along the long peduncle. It would be better perhaps to regard 

 the plant as a section of LeptocMoa rather than as a distinct 

 genus. Pournier has added three Mexican species of Uniola 

 which are unknown to me ; but, from his short characters, they 

 would scarcely seem to be true congeners. U. prostrata, Trin., 

 and its allies are now included in Distichlis. 



53. Distichlis, Eafln., comprises four or five closely allied 

 species, or perhaps varieties of a single one, extending from North 

 America down the Andes to extratropical South America, one of 

 them found also in Australia. They are generally, but not 

 always, maritime plants, with few spikelets nearly sessile in a 

 dense panicle, and generally if not always strictly dioecious, though 

 the two sexes diflFer but little in habit. The glumes are rather 

 rigid and paleaceous, which induced Link to join the only American 

 species with which he was acquainted, with the Mediterranean 

 Poa sicula, Jacq., as a genus Srieopyrvm, a name retained by 

 Presl and by ITournier for the American species. The European 

 S. siculum, however, and some African congeners have the spike- 

 lets hermaphrodite, a more regular bifarious inflorescence, and 

 otherwise differ sufiiciently from the American forms to be main- 

 tained as a separate genua which has a primary title to Link's 

 name. 



64. .ZELTJEOPirs, Trin. (CflZo^^ecfl!, Spreng., ChamcBdactylis,'SBeB), 

 has three species from the Mediterranean region. Central Asia, 

 and East India, formerly included in Dactylis, but diflering in 

 their creeping or prostrate branching habit, short, rigid, often 



