1889.] Botany. 1095 
whether free or more or less combined — and pubescence, if any, on 
them ; shape of the nectary ; style of the venation of the leaves, 
whether raised or impressed, etc. The specimens should be very care- 
fully dried, and subjected to as much pressure as will keep the leaves 
from wrinkling, but not so much as to crush the catkins altogether. 
The leaves should be so arranged that the underside of some of them — 
both the old, or lower, and the younger, or upper — be shown. 
The periods of growth when specimens should be taken is important. 
Male catkins should not be too old, but should be in full flower, and 
some with the pollen shed, so as to show the color of the empty anthers. 
Female catkins should neither be too young nor too old, and should 
illustrate the condition of the fully-developed stigmas. When it is 
possible, specimens in fruit should also be obtained, but not too old, 
as burst capsules are comparatively useless. 
The leaves should not be taken till they have arrived at maturity, 
and not, as a general rule, before the middle of August. Young leaf- 
specimens are sometimes useful as supplementary examples. It is im- 
portant, in taking leaf-specimens, to secure side-branches as well as 
shoots, since the character of the leaves on these is often different. 
In collecting willows every bush should be examined, not only when 
in flower, but when in leaf, and, if there is the least doubt about the 
species, specimens taken. Where more than one species grows together, 
a sharp look-out should be kept for hybrids, but hybrid forms occa- 
sionally occur at some distance from either of their parents. This may 
happen by the transmission of the seeds by wind or water, or by the 
parent bush, cross-fertilized by insect-agency, having died out. In 
looking for hybrids it must be remembered that frequently they do not 
show exactly intermediate characters, but often bear a close resemblance 
to one or other of the parent species. Such forms can be detected only 
by careful study, and an intimate acquaintance with specific characters." 
