44 Mr. Woods on the Genera of European Grasses. 



by many botanists. It differs from both in its one-sided head of flowers, and 

 I readily follow Link in making of it a distinct genus under the name of 

 Oreochloa. Sclerochloa dura has nothing in common with Sesleria either in 

 character or habit, nor can I understand what induced Linnaeus to join it 

 with Cynosurus. Its nearest affinity is that pointed out by Palisot de Beau- 

 vois with Sclerochloa procumbens, but this can by no means be separated 

 from S. maritima and the other Glycerice of Smith. Sclerochloa thus formed 

 is, I think, a natural genus, though it must be confessed that S. dura is very 

 different from the more delicate species, and especially from the Festuca ex- 

 pansa of Kunth, which yet seems better placed in this than in any other 

 admitted genus ; but the dichotomous inflorescence, thickened flower-stalks, 

 and connate glumes, might, if it had companions, make it the type of a sepa- 

 rate one ; Trinius accordingly has named it Sphenopus. 



The purple stain noticed in Poa between the thicker part of the palea and 

 its scariose transparent margin occurs also in Sclerochloa, and in some species 

 of Festuca and of Avena. I suspect it to have something to do with the struc- 

 ture of the parts, though I cannot point out the relation. 



I place with Sclerochloa two plants, not generally admitted into the genus, 

 Poa rigida and Triticum loliaceum. In the former, the outer palea is totally 

 without ribs and terminates in a small mncro, but its habit and one-sided 

 panicle agree very well with that of the genus. The latter absolutely differs 

 in nothing from the rest but in its nearly sessile florets ; and the branched 

 rachis and one-sided spiculse keep it very distinct from Triticum. Poa litto- 

 ralis, auct., is nearly allied in habit to Sclerochloa ; but the acute form and 

 decided mucro of the outer palea obliges me to join it to Festuca. 



Glyceria was established by Brown on Festuca fiuitans alone. Smith 

 added several species from Poa. Kunth transferred these to Festuca, preser- 

 ving from among them only G. aquatica in addition to the original species. 

 The two plants differ considerably in habit, and the latter has a panicle equal 

 all round, while in the former it is one-sided ; yet the structure of the flowers 

 is so similar that I cannot separate them. 



Eragrostis. Every botanist easily distinguishes this by its habit from Poa. 

 I think the nature of the outer palea, whose texture is equal throughout, while 

 \n Poa it is invariably firm at the base, and terminates in a scariose extremity, 



