1892, ] The Identification of Trees in Winter. 185 
leaf scar; the thorn is frequently branched, and its branches 
subtended by distinct bracts. - In Crataegus Crus-galli Linn. 
the thorn has two lateral buds, of which one exceeds the 
other considerably in size. The smaller bud usually perishes, 
the larger one develops, pushes the thorn aside, and in the 
older parts of the tree the thorn then assumes an apparently 
lateral position. In Maclura aurantiaca Nuttall there is usually 
a leaf bud on one side, and a long narrow scale with empty axil 
The fact that in certain species the thorns representing 
branches appear only under abnormal conditions, or first in 
the older Plants, reduces the value of thorns as constant 
features in distinguishing plants. Many ligneous plants also 
ave thorns which represent only outgrowths of the bark. 
These are usually irregular in their disposition, but the triple 
spines of Rives Cynosbati Linn., placed just beneath the 
Petiole-scar is a good instance of the constancy of character 
tai disposition sometimes shown by mere outgrowths of the 
ark, 
rae Scars, being frequently decurrent from the latter 
Sriren epulifolia Linn., fig. 13; Cercits Canadensis Linn. 
+ % “onymus atropurpureus Jacq., fig. 19). The more or 
iss rounded angles of other plants are also worthy at times of 
observation, as j 
angled stems 
. 40 addition 
ished by the a 
forming a sort 
Others which a 
Species, 
oho Color of the bark of twigs usually varies in shades of 
character; Stay. When therefore a tree or shru presents 
aero; "tically twigs with bark of a green color (Negundo 
u Moench, fig. 18; Sassafras officinale Nees; Euony- 
rele tPureus Jacq., fig. 1) or of various shades of red 
Olor b 
