TWO TYPES OF VARIABLE PUBESCENCE IN PLANTS 473 
to have several intergradations in the intermediate territory. Doubt- 
less all manuals of botany contain many overlooked cases of this kind, 
and specialists are even accused of describing two species from dif- 
ferent parts of the same tree. While the unnecessary multiplication 
of species is to be regretted, it is manifestly impossible for but few 
systematists to compare critically many related species from growing 
material and the difficulties of the authors of manuals are far greater. 
It is, however, urged that all botanists give more careful attention 
to observations of this character in the field and that a greater amount 
of discriminating collecting be done with respect to variations occurring 
upon individual plants. A very large number of descriptions in the 
manuals of botany make no mention of the color of the flowers or 
of conspicuous root characters. As the descriptions in these manuals 
must of necessity be largely drawn from dried and often inadequate, or 
discolored specimens, but little improvement in the descriptions can 
be expected until herbaria are supplied with field labels giving the 
necessary data. 
Bureau of Plant Industry, 
Washington, D. C. 
