ME. Q. BElfTHAU OU CHlAMnfE^. &5 



flowers, and the glume usually uiiawued ; but A. pidchella, "Willk., 

 with the glume awned, cannot be otherwise distinguished from 

 it. Periballia, Triu., is the A. involucrata, Cav., in which the 

 two flowers are as in A. agrostidea rather distant from each other, 

 the lowest flowering glume unawned, the upper one awned, but 

 both flowers hermaphrodite, as in the rest of the genus. The 

 inflorescence of this species is rather peculiar ; the lowest whorl of 

 branches of the panicle are usually without any or with only very 

 few spikelets, and were regarded by Cavaailles as an involucre : 

 but that is not always the case ; I have seen some specimens 

 with spikelets on all the branches. A. sabulonum, LabilL, from 

 New Caledonia, is a very doubtful plant. Labillardiere's figure 

 is a good representation of the Australiasan form of Sporobolus 

 virginicus, except that the spikelets are drawn as two-flowered. 

 The specimens sent for Labillardiere's plant by Pancher and by 

 Vieillard have only one flower in the spikelet. 



2. CoETiTEPHOKTJS, Beauv. (Weingartneria, Bernh.), comprises 

 two European grasses, extending into Worth Africa and more 

 sparingly to the Levant, with the continuation of the rhachilla 

 of Deschampsia, but readily distinguished by the peculiar articu- 

 late club-shaped awn of the flowering glumes. 



3. Deschampsia ( Oampeliaj Jjink) is a genus of about twenty 

 species, from the temperate or colder regions of both the New 

 and the Old World, sparingly represented in mountain regions 

 within the tropics. It bears the same relation to Aira that 

 Beyeuxia does to Agrostis ; the plants are usually perennial and 

 stouter than in Aira, the spikelets larger, and the rhachilla is 

 produced beyond the upper flower into a bristle often bearing a 

 tuft of hairs, and sometimes an empty glume on even a male 

 flower ; the flowering glumes are also frequently more or less 

 denticulate. No less than six of the species have been proposed 

 as distinct genera: — Vahlodea, Pries, is D. atropurpurea {Aira 

 atropurpurea, Wahlenb.), a northern species, with the flowering 

 glume not at all or only very minutely denticulate, otherwise 

 quite a Deschampsia. Avenella, Parlat. (Lerchenfeldia, Schur), 

 is the common D.flexuosa {Aira flexuosa, Linn.), with the flower- 

 ing glume surrounded by hairs. The grain is said by Parlatore 

 to adhere to the palea, which may be sometimes, but is certainly 

 not always, the case. Monandraira, Em. Desv., includes two 

 Chilian species, Trisetwn Berteroanum and T. airceforme of Steudel, 

 separated from Deschampsia as having but one stamen to the 



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