BUDS AND STIPULES. 257 
halfway down. The swelling of the axis completes this ope- 
ration later on. Salix phylicifolia var. Weigeliana often bursts 
along the anterior face, or irregularly ; but this appears to be due 
to the crippling of the bud by parasitic insects. 
2. There is sometimes a ridge on the posterior face corre- 
sponding to the line of union, as in S. alba and S. cinerea. In 
S. cordata there is a wide shallow groove at the same place. 
3. The anterior face during the expansion of the buds in spring 
becomes emarginate, bidentate or more or less deeply bifid at the 
upper end. S. alba and S. lucida are exceptions,” inasmuch as 
the anterior face remains entire. I have observedjno ridge, indi- 
cating union, on the anterior face ; but as this is generally absent 
or inconspicuous on the posterior face, it does not much invalidate 
the presumed cohesion of the anterior edges of the leaves. 
4. The strongest evidence, perhaps, of the presence of two 
leaves in the formation of the winter-seale, is that the latter is 
more or less strongly carinate on the edges, right and left, that is 
laterally. S. lunata, S. reticulata, and S. stipularis are ob- 
surely carinate. The inner face shows a number of longitudinal, 
parallel nerves, the two strongest of which occupy the position 
of the carina or keel, and correspond to the midribs of the 
two leaves. The midribs being right and left of the bud, agree 
with the insertion of the first two leaves of axillary buds, those 
leaves being generally at right angles to the leaf on the main axis. 
A curious case occurs in Salix cordata, S. iucida, and S. lanata. 
The inner and membranous face of the scale separates more Or 
less completely from the coriaceous outer one, and resembles a 
Second scale. It is, however, exactly opposite to the outer layer 
M the scale (not alternate), and is divided in the same way as 
the outer layer. 
Populus nigra, Linn., var. pyramidalis, Spach (fig. 115).—The 
n mal bud of the Lombardy Poplar is conical, angular, and 
ud mm. in length. Axillary or lateral buds are smaller and 
" angular, owing to the fewer scales in their composition. 
omis nes one or both of the stipules of two fallen leaves, not 
8 part of the terminal bud, persist through the winter. 
terminal i and second pairs of stipules forming part of the 
summer ud belong to leaves that developed during the previous 
ecause "i fell in autumn. They are the hardest of the stipu es, 
the fi ead. The third pair are larger, and to them belongs 
‘st leaf of the bud. The fourth pair are longer than the 
te 
