346 MR. G. BENTHAM ON COMPOSIT E. 
once recognized the plant as one of which we have good speci- 
mens from the same locality, and which Meyen placed in 
Baccharis (B. phyliceformis, Meyen) on account of its general 
affinity, but which Walpers invita natura transferred to Vernonia 
on account of the pappus. In these specimens the relative posi- 
tion of the hermaphrodite and female flowers is normal, although 
Nuttall’s genus can be sustained as distinct from Baccharis on 
other grounds. Sterility may be more or less perfect either in 
the central florets, extending outwards more or less to the greater 
portion or to the whole of the hermaphrodite ones, or in the 
female florets, but extending never, as far as I am aware, within 
the outermost row; or, in one and the same head, both the outer 
female and the innermost of the hermaphrodite florets may be 
sterile. 
In three of the principal tribes, Vernoniacee, Eupatoriaces, 
and Cichoriacez, uniform hermaphroditism of the florets is, I 
believe, quite constant, and the sterility of any of them (other 
than accidental) very rare and exceptional. So far, therefore, 
Linneus’s order of Polygamia æqualis is maintainable, the pre- 
sence of any female florets at once excluding from either of these 
tribes any plant supposed to belong to them; but the character 
goes no further as a tribual one. In Cynaroidex an outer row of 
female or neutral florets occurs in a few genera, but is not con- 
stant even in the same genus; in Mutisiacex it is more frequent 
and more constant. In the remaining eight orders the presence 
of one or more rows of female florets is the rule, but with ex- 
ceptions, sometimes in single species of large genera where it is 
usually constant, sometimes in the majority of species or in whole 
genera, and in two subtribes of Inuloidez very prevalent or quite 
constant. In allthese cases we are therefore obliged to be very 
eautious in making use of the homogamous or heterogamous 
flower-heads as an absolute generic distinction. Still less value 
can usually be attached to the sterility of the inner or outer 
florets, although in some cases it appears to be positively generic 
or even subtribual. The central hermaphrodite and outermost 
female row of florets are constantly sterile in some Calendulaces, 
all the hermaphrodite florets constantly sterile in the subtribes 
Milleriew, Melampodiex, and Ambrosiew, of Helianthoidex, and in 
some genera of other subtribes ortribes; in other genera the greater 
or less sterility of the central florets is of no more than specific value. 
The sterility of the circumferential florets (reduced in that case 
