PROF. T. H. HUXLEY ON THE GENTIANS. 111 
Such are the types or leading modifications of floral structure 
which I have met with; and such the evidence, taken together 
with the extant descriptions of the forms I have not examined 
personally, on which I base the conclusion that they embrace all 
the most important morphological modifications of the corolla 
which the Gentianes offer. It will be observed that, unfortu- 
nately, they do not exhibit any particular relation to the received 
family, or even generic, groups. The accepted genus Gentiana, 
for example, exhibits no fewer than five of the eight types of 
floral structure; while the Lissanthe type is exhibited by some 
five-and-thirty accepted “genera.” If Frasera and Swertia 
are to be regarded as generically distinct from Gentiana, I fail 
to see on what principle G. gmarella and G. purpurea, which 
differ at least as much from one another as Swertia, Frasera, 
and Gentiana do, can be grouped into one genus. Consider- 
ations of this kind, which might be multiplied indefinitely, 
obviously suggest a thorough revision of the taxonomy of the 
Order—a task which I certainly shall uot presume to attempt, but 
which will, I hope, be executed by some one more fitted to take 
such a large and difficult piece of work in hand. 
Another important conclusion, which is naturally suggested by 
the facts to which I have drawn attention, is that the several 
types in each of the two series beara certain progressive relation 
to one another. It is obvious that Actinanthe and Asteranthe are 
the simplest and least modified forms in each series; that Ste- 
phananthe is the most differentiated of the Perimelite ; that Pty- 
chanthe and the more specialized forms of Lissanthe are the most 
differentiated of the Mesomelite ; while Lophanthe and Kera- 
tanthe in the one series, Limnanthe in the other, constitute 
lower grades of differentiation, though they are nowise to be 
regarded as transitional between any of the others. 
Thus, on purely morphological grounds and as a mere generali- 
zation of the facts, without the introduction of any speculative 
considerations, the relations of the various types may be repre- 
sented thus :— 
