32 Mr. Woods on the Genera of European Grasses. 



PiPTATHERUM is a geiius of 4 or perhaps 5 species, all European, which were 

 separated by Palisot de Beauvois from Jgrostis and Milium. Kunth says of the 

 spiculoe of Pii'TATHERUM, " hasi iiaud articidatee." I am ignorant of the precise 

 import of this ptirase. None of the Stipuceœ are described as having- the spi- 

 culœ articulate at the base. Such a character might well be given to a phmt, 

 for instance, like Impcratti n/litidricu, where the whole spicula, glumes in- 

 cluded, readily separates from the callus whicii supports it. In Melica also 

 the calyx appears to fall off; but in most Grasses the separation of the floret 

 takes place within the glumes, and tliis seems to be the case with all the 

 Stipaceœ. In -S'. aristella the floret is sessile, and the awn neither geniculate 

 nor twisted ; perhaps it ought to form a distinct genus, or be united to Pipta- 

 therum. In the Mantissa it is called a,n Agr-ostis. In all the other species the 

 awn is geniculate and generally with two knees, which, however, are not very 

 acutely bent. The part between the knees is less closely twisted than the 

 lower part of the awn, but in the same direction. Two broad ribs run down 

 the awn, and each side of each rib is furnished with a row of hairs, which in 

 some species are siiort and bristle-like, in others soft and long, or bristly in 

 the twisted part, and longer and finer in tliat which is not twisted. Duby in 

 the Hot. Gall, describes .S'. capillata " aristis basi rectis apice tortilibus ;" but 

 this is certainly erroneous. I have preferred the name of Achnatherum given 

 by Palisot de lieauvois to the inadmissible compound Lusiagrostis adopted 

 from Link by Kunth. It is true that some species were included by the first- 

 mentioned writer, which succeeding botanists do not acknowledge ; but as 

 these are sunk in other genera, they form no objection to the appropriation of 

 the name to this. In habit the European, and probaldy the Niberian species 

 approach to ^îruiido. 



ARUNDINACEiE. 



This tribe, like the following, contains some plants of which the spiculœ are 

 one-flowered, and others in wliich they are many-flowered, but with so much 

 similarity of habit and structure, that Linnœus united them all into one genus. 

 I follow other botanists in finding the technical difference in the long silky 

 hairs which envelope the florets, but I confess it to be a nice point to di- 

 stinguish the tribe on this ground. fSome species of Agrostis, as has been 

 already observed, are not entirely destitute of such hairs, and nearly if not 



