ME. G. BENTHAM ON GEAMINEiE. 125 



Foa notwithstanding the adherence of the grain to the palea. 

 Leucopoa, Grriseb., is the temperate-Asiatic P. alhida, Turcz., 

 with the spikelets rather larger than usual, and somewhat sca- 

 riose and shining glumes like those of several Chilian species. 

 Bioicopoa, E. Desv. {Dispar, Doell), is a section proposed for 

 P. chilensis, Trin., P. lanuginosa, Poir., and their allies, in which 

 the spikelets are usually, but perhaps not always, dioecious. In 

 the dried state there is very little external difference between 

 the male and the female panicle ; and there are certainly Chilian 

 specimens otherwise very near P. chilensis which have herma- 

 phrodite flowers. Doell also places P. lanuginosa in his herma- 

 phrodite section, whilst Emile Desvaux describes it as dioecious, 

 as I have generally found it, The stamens, however, are very 

 deciduous, and the ovary at the time the stamens are still enclosed 

 very minute ; and it requires careful observation to ascertain the 

 real absence of the one or the other. It is probable that many 

 species hitherto supposed to be perfectly hermaphrodite are more 

 or less polygamous. P. lanuginosa shows, moreover, an appi'oach 

 to Festuca in the fine though short points to the flowering glumes, 

 and in the adherence of the grain to the palea. Poidimn, Nees, 

 a Brazilian species, was separated by I^ees from Poa on account 

 of a reduction in the number of flowers to one or two, which Doell 

 finds to be by no means constant. 



63. Oolpodium:, Trin., about ten species, from the Levant and 

 Eussian Asia, might perhaps be regarded as a section of Poa. 

 It diflfers in very little besides the small spikelets containing only 

 one or two flowers, thus connecting Poa with the Agrostese. 

 The arctic plant, published by E. Brown as a doubtful Oolpodium, 

 now forms Grisebach's genus Arctagrostis, included above under 

 Agrostese. 



64. G-EAPHEPHOETJM, Desv., including Scolochloa, Link (Plu- 

 minia, Fries), and Dvpontia, Br., contains seven North-American, 

 North-European, or North- Asiatic species, very well worked up 

 and distributed into four sections by Asa Gray. They are all 

 very near Qlyceria, differing chiefly in the hairs surrounding the 

 flowering glumes, which induced several botanists to refer the 

 genus to Arundinese, though very different in habit and in the 

 shape and venation of the glumes. The hairs of the spikelets 

 are, moreover, very variable, shorter than in true Arundinese, very 

 short in the section Arctophila, and not entirely abseot in one or 

 two species of Qlyceria. 



LINN. JOTJKN. — BOTANY, VOL. XIX. L 



