124 PROF. T. H. HUXLEY ON THE GENTIANS. 
tion to deny that, in the absence of all other phaanogamous vege- 
tation, the Gentians might have occupied every region and 
station ou the earth's surface in which flowering plants can exist ? 
Is there any ground for seeking the causes of their distribution 
elsewhere than in the competition with other plants which they 
have undergone and are undergoing, and in the course of which 
it has often happened that the success of a given form in adapting 
itself to certain conditions has involved a corresponding diminu- 
tion of the faculty of adapting itself to others? 
Such are the observations I have to offer. I call them 
“Notes and Queries ;” and I am afraid there are more queries 
than notes. My hope in offering them to the Society is to 
stimulate those who are better qualified than I am to carry 
through a serious botanical inquiry, and who have more time 
before them than I have to take up the subject. I believe that 
the systematic and exhaustive study of a single well-chosen 
Order, and of all the biological problems which it’ presents, would 
inaugurate a new era in the progress of Botany. The amount 
of patient and sagaciously directed labour which is embodied 
in our standard systematic works is astounding ; and the deepest 
gratitude is due to those who have thus brought the data of 
Vegetable Morphology and Distribution into a shape in which 
they can be dealt with. But from the point of view of the Evo- 
lution doctrine, it is obvious that Taxonomy and Distribution 
have to be subjected to a process of revision, which will hardly 
fail to revolutionize both. 
DESCRIPTION OF PLATE II. 
A scheme to illustrate the morphology of the flower of the Gentianez. 
