THE WILLOWS OF OHIO. 299 



Salix criocephala 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 5". cordata in 

 leaf but its upright habit and the coarse serration as contrasted 

 with the sprawling habit and sharp-toothed leaves of 5. 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 5. 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 humilis 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 5. Candida, but ordinarily it is a gray 

 plant while 5. Candida has snowy white wool on the under side 



Plate X. Salix humilis and variety tristis. 



Series of leaves from 5. humilis (lower row) 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. 



