THE WILLOWS OF OHIO. 299 
Salix eriocephala Michx. of Britton’s manual includes those 
forms with ferruginous hair on the leaves and tomentose twigs. 
Salix prinoides Pursh, is a narrow leaved form of the type. 
It is common in swamps all over the state. 
This species is most difficult to separate from S. cordata in 
leaf but its upright habit and the coarse serration as contrasted 
with the sprawling habit and sharp-toothed leaves of S. cordata 
are sufficient to distinguish them. As described under Salix 
bebbiana it sometimes connects with that species. Narrow revo- 
lute-leaved forms are sometimes found which connect this species 
with S. humilis, probably some of them are hybrids. 
SALIX HUMILIS Marsh. PRAIRIE WILLOW. 
A shrub not more than 3 meters tall with spreading often re- 
cumbent branches. Leaves oblong or spatulate, gradually nar- 
rowed to the base, abruptly acute and sometimes mucronate at 
the tip, mostly revolute, entire to undulate-dentate, puberulent 
or glabrous above, tomentose, especially on the prominently rais- 
ed veins beneath. or glabrous and glaucous, primary veins rather 
distant, inclined to be horizontal, looping or oftener branching 
and arching, with several costals between them, secondaries 
quite irregular, catkins born very much as those of S. discolor, 
long before the leaves but smaller than in that species, from 
short stubby pussies, staminate 2 cm. long or shorter, carpellate 
occasionally 4.5 cm. in fruit, bracts small or none, scales dark- 
ened above, long pilose on the back, glabrous in front, capsules 
elongated, often rostrate-conic in fruit, hirsute at least when 
young, pedicelled, sometimes almost 1 cm. long when ripe, style 
distinct, red. 
Salix humilis though common nowhere is generally distri- 
buted over the state. It will probably be found growing on dry 
hillsides in nearly every county. 
In most forms Salix humulis is easily recognizable in leaf 
because of the long narrow revolute leaves. In flower it is char- 
acterized by the short stubby pussies from which the flowers 
come. The leaves of the ranker shoots take on an appearance 
very similar to those of Salix discolor. It is from such branches 
that many of the so-called hybrids of our herbaria came but real 
hybrids undoubtedly do occur. Sometimes also the present 
species is very similar to S. candida, but ordinarily it is a gray 
plant while S. candida has snowy white wool on the under side 
Plate X. Salix humilis and variety trestis. 
Series of leaves from S. humilis (lowervrow) connecting with the va- 
riety tristis (upper row); flowering aments from var. tristis, fruiting from 
S. humilis; natural size; capsule from S. humilis drawn in with camera 
lucida, enlarged five times. 
