2 Mr. Woops on the Genera of European Grasses. 
In my younger days I never found myself at a loss to distinguish Arundo 
from Avena on the one hand, or from Agrostis on the other, or Festuca from 
Triticum; yet I now observe that many species of Avena and of Agrostis have 
hairs at the base of the florets, and that in Arundo they are not always long. 
The hairs of Avena fatua, A. sterilis, &c. cover great part of the outer palea, 
and are more rigid than in Arumdo; but the hairs in Arundo are not strictly 
confined to the base, and Avena setacea bas soft hairs rising from the base to 
more than half the length of the palea. They are both absolutely and rela- 
tively longer than those of Arundo ( Deyeuxia) sylvatica, Avena has a jointed 
awn twisted at the base; but this is also the case, though less obviously, in 
some species of Arundo. Again, Aira is distinguished from Avena by having 
only two flowers, but Avena subspicata, A. setacea, and some others have 
hardly, if ever, more than two flowers. The characters of Avena and Bromus 
in the English Flora seem to differ only in the adhesion of the seed in Bromus 
to the inner valve alone of the corolla, while in Avena it is said to be united 
to both valves. This peculiarity is not found in all the species of Avena, in 
some of which the seed, though inclosed in the hardened paleze, is not united 
to either. Yet Sir J. E. Smith is among the botanists who are most exact in 
their descriptions, and most careful to make them contain some points of dif- 
ference. That the outer palea is somewhat more rolled in at the edges, and 
the inner somewhat more ovate, in Avena, are minute and comparative points 
of difference, hardly sufficient for the foundation of a genus, 
more constant than I find them to be. 
The manner in which a single species is transferred by different authors to 
different genera shows that I am not singular in finding great difficulties in 
this particular. Arundo tenella is an Agrostis with Roemer and Schultz. 
Holcus, as separated from Sorghum, is united by De Candolle to Avena, while 
Kunth places it among the Phalaridee. Bromus pinnatus of Linn. and of 
Eng. Bot. became Festuca pinnata with later botanists, and the alteration was 
afterwards adopted by Smith himself. Haller called it Triticum, 
is followed by De Candolle. P. de Beauvois formed for it a se 
under the name of Brachypodium, from the short 
even if they were 
in which he 
parate.genus 
stalks on which the spiculæ 
are placed. Mertens and Koch, after paring away many species from this 
genus, still left in it B. pinnatus, and some other closely allied perennial 
