THEIR FORMS AND FUNCTIONS. 529 
cave, gummy, folded over the bud, and having their edges in 
front of their own petiole, so that they protect younger members. 
The outer or exposed ones of the winter-bud are reddish brown, 
and elongate to some extent with the developing bud in spring. 
The inner ones attain a much greater length, and are narrower 
and green; all are caducous. 
The terminal bud is, in winter, covered by several pairs of 
stipules, some of which belonged to leaves which fell in autnmn. 
Some of the reddish-brown stipules, however, have well-developed 
leaves. About two or three pairs cover the winter-bud, while 
one or two pairs cover the growing one. The axis is therefore 
continuous, and all the leaves apparently are perfect. 
Axillary buds remain comparatively small till spring, and are 
protected by scales which are modified stipules, as in the ter- 
minal bud. 
While in Populus the buds are protected by the stipules, in 
Salix the stipules are small, and this function is performed 
mainly by the leaves. Thus in 8S. cuprea the winter-bud is 
covered by a pair of leaves reduced to brown scales which are 
connate, forming a cap splitting along one side in spring and 
partly along the other. Each of these modified leaves has a 
strong midrib or shallow keel. Succeeding leaves are very silky 
or tomentose beneath, and perfect; or one to three of them 
may, under certain conditions, remain small, dry up, and fall 
early. 
The stipules are very small, tooth-like, ovate, silky, ciliate, and 
the lower ones fall early, or withering, remain for some time on 
the stem. They seem to be functionless, as far as the protection 
of either terminal, axillary, or winter buds are concerned. 
The axillary buds, which alone are designed to produce the 
branches next year, are completely hidden and protected by the 
deeply concave base of the petiole. 
The stipules, however, though always very small in bud, and 
in some species (8. retusa, Grahami, cuprea, repens, &c.) per- 
manently so, in others become larger, and in some (8. dasyclada, 
myricoides, &c.) attain a considerable size. Their chief function 
appears to be to protect the axillary buds, which are also sheltered 
by the dilated and concave bases of the petioles. 
Masters, in his ‘ Vegetable Teratology,’ mentions (p. 357) 
an increase in the number of stipules in Salix pendula; a mon- 
strosity which gave rise to the variety multistipulata, Seringe. 
