ME. G. BENTHAM ON GEAMINEiE. 121 



of characters. The long narrow spikelets are few or numerous 

 in a long, rigid, terminal unilateral spike ; and the exceedingly- 

 long capillary styles become spirally twisted together far beyond 

 the glumes. There is a considerable variety in the number 

 of spikelets, in the number of flowers in each from one to 

 four ; and even the stamens and styles are sometimes two, some- 

 times three ; but I have been unable to trace any connection of 

 these diversities either with each other or with geographical 

 stations so as to mark distinct species. 



49. Zeugitbs, Schreb. (Senitis, Adans., Bespretzia, Kunth, 

 KrombhoUzia, Pourn.), has five or six tropical -American species. 

 They have not all the tall habit of the preceding genera ; for the 

 best-known West-Indian and Central-American species, origi- 

 nally described by Linnseus under Apluda, is a much weaker 

 plant with smaller leaves ; they are, however, broad and flat, 

 with the characteristic venation of the subtribe. The spikelets 

 in the genus generally have one fertile flower with two to five 

 male ones above it. 



I have already adverted to our eighth and last subtribe Mufes- 

 tucece, or Festuceae proper, as difiering from Eragrostese in having 

 five or more nerves to the flowering glumes instead of three or 

 one only. Generally speaking, they have not the several-awned 

 glumes of PappophoresB and Triodieae, nor the barren spikelets nor 

 long styles of Sesleriese, nor the long hairs surrounding the 

 flowering glumes of Arundinese, nor the cluster of upper empty 

 glumes of Meliceee, nor the peculiar foliage of CentothecesB ; yet 

 there are here and there exceptional species showing an approach 

 to one or another of these characters, and interfering much with 

 any definite line of demarcation. We include in the subtribe 

 twenty genera, the last five of which are further characterized by 

 the adherence of the grain to the palea ; but, as already observed, 

 this character is not quite constant even in Festuca, and is occa- 

 sional in such genera as Foa and Briza, where the grain is 

 usually free. I have been unable to discover any other cha- 

 racter which would distribute the genera of the subtribe into 

 more satisfactory groups. 



The first two genera have a simple racemose inflorescence. 

 50. PiETiEOPOGOTr, Br. {LophocJilcsna, Nees), has three species, 

 one arctic, the two others Californian, distinguished by the keels 

 of the palesB bearing a linear tooth or flat crest ; and 51. Betl- 

 EiNiA, r. Schmidt, a single Japanese species, with two empty 



