BOTANY OF TERRA AUSTRALIS. 57 



of the inner series is produced while its corresponding 

 stamina are generally wanting. This may, no doubt, ac- 

 tually be the case, but as it would be, at least, contrary to 

 every analogy in Monocotyledonous plants, it becomes in a 

 certain degree probable that the inner or proper envelope of 

 grasses, the calyx of Jussieu, notwithstanding the obliquity in 

 the insertion of its valves, forms in reality the outer series of 

 the true perianthivim, whose inner series consists of the 

 minute scales, never more than three in number, and in 

 which an irregularity in some degree analogous to that of 

 the outer series generally exists. 



It is necessary to be aware of the tendency to suppression 

 existing, as it were, in opposite directions in the two floral 

 envelopes of grasses, to comprehend the real structure of 

 many irregular genera of the order and also to understand 

 the limits of the two great tribes into which I have pro- 

 posed to subdivide it. 



One of these tribes, which may be called PanicejE, com- 

 prehends Ischsemum, Holcus, Andropogon, Anthistiria, 

 Saccharum, Cenchrus, Isachne, Panicum, Paspalum, Rei- 

 maria, Anthenantia, Monachne, Lappago, and several other 

 nearly related genera ; and its essential character consists 

 in its having always a locusta of two flowers, of which the 

 lower or outer is uniformly imperfect, being either male or 

 neuter, and then not unfrequently reduced to a single valve. 



Ischsemum and Isachne are examples of this tribe in its 

 most perfect form, from which form Anthenantia, Paspa- 

 lum, and Reimaria, most remarkably deviate in consequence 

 of the suppression of certain parts : thus Anthenantia 

 (which is not correctly described by Palisot de Beauvois) 

 differs from those species of Panicum that have the lower 

 flower neuter and bivalvular, in being deprived of the 

 outer valve of its gluma; Paspalum differs from An- 

 thenantia in the want of the inner valve of its neuter 

 flower ; and from those species of Panicum, whose outer 

 flower is univalvular, in the want of the outer valve of its 

 gluraa; and Reimaria differs from Paspalum in being 

 entirely deprived of its gluma. That this is the real 

 structure of these genera may be proved by a series of [sss 



