20 Mr. Woops on the Genera of European Grasses. 
are barren in some genera and perfect in others. The glumes are firm, nearly 
equal, inclosing the pale, which are thin, and often filmy, but bearing a 
strong awn. The inflorescence is panicular, except in Andropogon, where 
most of the species produce their spiculæ in two rows on the same side of a 
flattened rachis; and the spikes or racemes thus formed are frequently dis- 
posed in pairs or digitate. Flowers in determinate sets occur among the 
Paniceæ, which, however, are easily distinguished by the coriaceous paleæ. 
They are also found in Hordeum, and in some foreign genera among the 
Rottboelliacee. Elymus and Lygeum have two or three spiculæ together, 
but they offer nothing of a systematic arrangement. 
The genera of this tribe may be thus disposed : 
A. Spicule all fertile, clothed with long silky hairs. Glumes thin. 
1. Saccharum. Pale unarmed, the inner small or wanting. Squamulæ 2. 
Panicle not spike-like. 
2. Imperata. Paleæ 2, unarmed. Squamulæ none. Panicle spike-like. Rachis 
abruptly flexuose, continuous. 
. Erianthus. Outer palea awned. Squamulæ 2. Panicle spreading. Rachis 
hardly flexuose, very brittle. 
Oo 
B. Lateral or stalked spicule barren. 
— 
. Andropogon. Spiculæ linear-lanceolate, compressed. Seeds nearly linear. 
. Sorghum. Spiculæ ovate or ovato-lanceolate, turgid. 
tile floret coriaceous or horny. Seed roundish. 
e 
Glumes of the fer- 
The second and third genera were struck off from Saccharum by Palisot de 
Beauvois. The true Saccharum has, as it appears from this author, only one 
palea and no awn or seta. 
Imperata and Erianthus differ, as stated above; but these distinctions are 
not sufficient to constitute genera unless supported by a marked peculiarity of 
habit; and where we have only one species of a genus, as in Imperata, we can 
hardly acknowledge some difference of general appearance to decide the 
question, since we have no proof of its having any connection with the cha- 
racter. I may add to the foregoing description of Imperata, that in all my 
specimens the styles are united in the lower part. The very tough and horny 
