10 Mr. Woops on the Genera of European Grasses. 
12. Rottboelliaceæ, 11 genera, 3 of which occur within my limits, Nardus, Psi- 
lurus, and Lepturus. 'This latter genus includes the European species 
of Rottboellia. 
13. Andropogoneæ, 26 genera. Imperata, Erianthus, and Andropogon are all 
with which I am concerned. The last-mentioned genus is made by 
Kunth to include Sorghum of Smith. 
Of this distribution we may observe, that the structure of Lygeum is so 
peculiar that we can hardly gain any thing by uniting it with others into a 
particular tribe, and that Zea, although described as having an external neutral 
floret in the fertile spicula, has yet no very striking general similarity with 
Phalaris, and still less with Alopecurus and Phleum, or these with Holcus and 
Anthoxanthum. Knappia, with its flowers on a one-sided rachis, may possibly 
be more nearly allied to the Chlorideæ, where it is placed by Reichenbach: 
yet on the whole I am disposed to keep it in the neighbourhood of Agrostis. 
Among the Paniceæ, Milium effusum seems oddly introduced between the two 
closely allied genera Paspalum and Panicum. To make out its claim to a 
place in the Paniceæ, we must suppose that of the two very similar outer 
glumes, which are usually considered as forming the calyx, one only deserves 
that name, while the other is to be taken as an abortive floret. These suppo- 
sitions (unsupported by any peculiarities in the construction) may afford 
grounds for ingenious speculations, but they can hardly be made use of as 
parts of a generic character; or, to use the words of De Candolle, “such an 
hypothesis may be convenient if considered as an image or a metaphor, but 
can hardly be allowed as an expression of reality." 
Kunth has not only scattered into three genera the species of the Linnean 
genus Milium, but he has placed these in three different families, Milium 
effusum, retaining the ancient name, is, às we have just seen, put among the 
M M. cœrulescens, M. paradorum, &c. form the genus Piptatherum, 
which is one of the Sfipacee ; and M. lendigerum, under the name of Gastri- 
dium, is found among the Agrostidew. The Arundinaceæ consist entirely of 
genera formed out of the Linnean Arundo. The Chloride are, perhaps, not 
very closely allied, at least there seems little affinity between Cynodon and Spar- 
tina except in the inflorescence. Keeleria among the Festucaceæ trenches very 
