14 Mr. Woods on the Genera of European Grasses. 



I have already noticed Zea as the only Grass within my limits where the 

 barren and fertile flowers are on different parts of the plant. I may add, that 

 it is the only one where there are no spiculse containing all the parts necessaiy 

 for the reproduction of the plants. Hordeum, Andropogon, and Sorghum have 

 distinct antheriferous spiculse mixed with the perfect ones. Holcus, Hierochloa, 

 and Arrhenatherum have barren florets containing anthers only, mixed with 

 the perfect ones in the same spicula. The Phalaridece and Panicece have one 

 or two abortive external florets ; this occurs also in Phragmites, and some- 

 times in Ampelodesmus. The addition of an upper abortive floret occurs in 

 many Grasses, as well in the many-flowered ones as in those which have but 

 one perfect floret, and perhaps may serve as an accessory in determining the 

 genus of a Grass, though I think it cannot always be depended upon even as 

 a specific character. 



Passing from the external to the more central parts of the plant, we find 

 that the glumes are wanting in Leersia, Coleanthus, and Nardus. They are 

 separated by a short stalk from the lower floret in Oryza, Stipa (except in 

 S. aristella), and Cynosurus aureus, solitary in Lolium, Psilurus, and some spe- 

 cies of Lepturus. On one side of the spicula in Elymus, Hordeum, and the 

 remaining species of Lepturus, and in some degree in ^gilops. The general 

 arrangement presents us two glumes on opposite sides of the spicula, but one 

 sometimes a little lower than the other, the inner or upper being rather the 

 largest. The terms inner and outer with respect to glumes may be used 

 either in relation to the spicula to which they belong, or to the spike or branch 

 of which the spicula forms a part. In the first case, outer and lower would be 

 equivalent ; in the second, the lower glume becomes the inner one in, I believe, 

 all cases where it can be precisely determined, except among the Rottboelliacece. 

 We see it clearly in Lolium ; but in most of the spiked Grasses, where the ar- 

 rangement is most evident, the position of the glumes seems to be equidistant 

 from the general centre. To avoid ambiguity, I use with Kunth the terms 

 upper and lower as applied to individual spieulae, inner and outer to the more 

 general inflorescence. Of the palese we must speak always with reference to 

 the spicula of which they form part, and the terms are synonymous. The 

 comparative size of the glumes is taken for granted in the description of most 

 Grasses. It is enough to notice the exceptions where they occur. The outer 



