88 ME. a. BENTHAM ON GRAMINEiE. 



distinct Bpecies (U. ripens, Beath.) with a still longer and nar- 

 rower rigid spikelike panicle often interrupted ; and the spikelets 

 are small, with membranous glumes, as in the typical U. siricta, 

 Presl, but awnless or nearly so. 



21. BAroHEA, Fourn., a single Mexican species unknown to me, 

 might perhaps be reduced to JEpicampes, from which it is said to 

 differ chiefly in a great inequality of the two empty glumes. 



22. Ageostis, Linn., even after being shorn of a number of 

 heterogeneous plants ascribed to it at various times from general 

 aspect, and after the suppression of numerous names given to 

 local representatives of cosmopolitan species, is still a genus 

 of nearly a hundred species, generally spread over nearly the 

 wliole world, but especially common in the temperate regions 

 of the northern hemisphere. Among the Buagrostese without 

 any continuation of the rhachilla they are generally known 

 by the absence of those peculiarities which have induced the 

 separation of several of the preceding as well as of the follow- 

 ing genera, by the thin short broad flowering glume with the 

 dorsal awn below the middle, and by the palea not more than 

 half as long as the glume, and often quite minute or even defi- 

 cient ; the panicle is also usually loose, very elegant, with nume- 

 rous small spikelets or almost capillary branches and pedicels. 

 There are, however, here, as elsewhere, exceptional species which 

 defy all neat classification ; even the dorsal awn is sometimes re- 

 duced to a minute tubercle, or only to be guessed at by the abrupt 

 termination of the central nerve of the glume. The American 

 species in which the palea is minute or deficient formed Michaux's 

 genus Trichodium, which has been extended to the European 

 A. canina, Linn., and others witli that character, to which Beau- 

 vois restricted the Linnean name Agrostis, whilst he gave the name 

 of Agraulus to the species in which the palea is more developed. 



23. CH.a;TrB.rs, Link, is a single Spanish annual, much like 

 some species of Agrostis, but anomalous in the group in having 

 the lowest (empty) glume larger than the others, and produced 

 into a long awn, whilst the flowering one, though shaped as in 

 Agrostis, has no awn. The inflorescence is also peculiar, each 

 branch of the panicle terminating in the three shortly pedicellate 

 spikelets. 



24. Aectageostis, Griseb., is a single arctic species, referred 

 by Brown doubtfully to Trinius's genus Oolpodium, but which 

 appears to be more nearly allied to Deyeuxia. It is, however, 



