36 © Distinguishing Species of Populus and Fuglans, etc. [Januaty, 
Fuglans nigra,—The pith of this species consists of thin plates 
running transversely, leaving open cavities between them. The 
pith is of a light-brown color. On a thrifty branch the bud scar 
is nearly heart-shaped with vertical and transverse diameters 
about equal. A very small bud can be seen in the sinus of the ~ 
scar. Above this is a larger bud, most of which is also within — 
the sinus of the leaf scar. Above these buds is a third one, still 
larger. The transverse diameter of the Jeaf scar is about equal. 
in length to the distance between the leaf scar and the tip of the — 
upper bud. A side view of the leaf scar shows quite a sharp — 
depression in the middle. On slender branches the bud scars are 
laterally compressed or appear longer: than on stout branches. 
Fig. 5, a 4c d, illustrate this species. ; 
Fuglans cinerea—The pith is separated in plates. It is of a 
dark brown color and in a narrower cavity than that of F migra. 
The leaf scar on a thrifty growth is not unlike the shape of a 
sheep’s face. The scars left by the woody bundles of the leaf are — 
shown in the drawings of all the species above mentioned. To- 
wards the lower part of a branch, one bud only appears above : 
the leaf scar; farther up on thrifty branches two buds may be 
seen. -The scar is without any sinus or depression at the top. 
In this species, on the middle of rapid growth, the upper bud is _ 
from one-fourth to two-thirds of an inch or even more above the — 
top of the leaf scar. Along the top of the leaf scar is a trans- 
verse or curved ridge or crest resembling velvet or plush. This” 
crest is not present in ¥ nigra, but is rarely if ever absent in F ; 
cinerea. The bark on a thrifty branch of * nigra when one yeat — 
old is about a third thicker than that on branches of %. cinerea of : 
the same age and size. After the first year, and sometimes — 
sooner, the outer bark of ¥. nigra cracks and rolls up in scrolls, | 
while the outer bark of ¥ cinerea shows nothing of the kind. Fig 
6, a 4c d, illustrates this species. 
The young trees of these two species of Juglans are not easily 
distinguished by the leaves. In the axil of the leaf of ¥ cinerea, — 
even when quite young, can be seen the velvet ridge. The odors — 
of crushed leaves of the two species are different. 
Some observations lead me to believe that many ether 1 trees 
and shrubs can be equally well distinguished by the young | 
naked branches, while in some cases it will be difficult to find 
good specific characteristics The drawings for this paper were 
made by W. Holdsworth. , 
