AGAVES OF THE UNITED STATES. 51 
For all these reasons, it is very difficult for a student in 
the laboratory to decide upon the limits of a species or a 
variety, or to make satisfactory descriptions. An unsigned 
article* has recently appeared in one of our journals whose 
writer, while advocating the founding of a garden in Ari- 
zona for the cultivation of plants peculiar to our arid region, 
is led to say: "No group of American plants, with the 
exception, perhaps, of the Cacti, is more difficult to under- 
stand from specimens preserved in herbaria, and not much 
light is thrown upon these plants [Agaves], by the occa- 
sional isolated individuals which drag out a more or less 
miserable existence in the confinement of northern glass- 
houses. Labor expended in herbaria in the study of the 
plants we have mentioned, is practically thrown away, as 
it can only be partial, and never final." 
Veiy little of our work can be regarded as complete or 
*' final," and we should accomplish little if our efforts 
should cease for that reason. A desert garden would be 
a valuable acquisition. I can think of various questions I 
should like to see tested in a place where these plants could 
be systematically observed and compared under natural 
conditions, and where experiments could be well controlled. 
In the absence of such a garden, however, I think that 
much can be done in laboratory and field if good specimens 
are collected, and proper studies made. 
We should be much assisted in forming correct ideas of 
the genus and the affinities of its species, if collectors would 
take habit photographs of the plants in their natural sur- 
roundings. Mr. C. G. Pringle, and Dr. T. E. Wilcox, have 
done valuable work of this sort. 
When practicable, living plants should be sent to botan- 
ical gardens where they will receive care and study. 
In this paper I have tried to bring together such informa- 
tion as I could gain concerning our Agaves from library, 
herbaria, conservatory and field, and to add what it was 
* " An Arizona Agave." Garden and Forest, May 8, 1895. 
