186 The Botanical Gazette. [June, 
distinguishing species. The little circular ruptures in the 
bark of Sayebucus Canadensis Linn., fig. 37; and the milky 
juice exuding from the broken bark of Morus rubra Linn., 
g. 5, in warmer weather are also good characteristics. 
Again, the pith at times affords good features, Thus in 
Diospyros Virginiana Linn., the place of the pith is usually 
hollow; in Gymnocladus Canadensis Linn., fig. 31, the pith 
is reddish brown; in species of Fuglans, fig. 20, and Plero- 
carya Caucasica Kenell, fig. 23, there is a tendency for the 
pith to separate into transverse plates. 
The more special examination of the form of the petiole 
scars with their intersected fibrovascular bundles, the relative 
genus. Naturally there will be the least difficulty in recoS” 
izi ; « been best 
studied during spring and summer by ordinary botanical me- 
~ very well known. eS re 
In addition to these more omnipresent characteristics pe : 
are others which are very good if present. Such are wes ‘e 
stance the form and character of the flowering buds for ee 
year, whether present in the shape of naked ca 
s flor 
aera 
inn., fi ; Cornus paniculata L'Her., fig. 36% wih 
the larg© 
f 
the scaly winter buds is often indicated only ee as com 
size of those scaly buds which contain flower ud 
It 
pared with those which contain only rudimentary leaves. 
