The Willows of Ohio. 
THE GENUS SALIX AND ITS RELATIONSHIPS. 
The willow family contains but two genera, Salix and 
Populus. These, in most cases distinct enough in their leaves 
are separated by the following floral differences. Populus has 
fimbriate scales, cup shaped discs, elongated stigmas and many 
stamens, while Salix has entire or only slightly crenate scales, 
mostly glandular clavate discs, short stigmas and few stamens, 
two in the majority of the species. In the polyandrous willows 
which are treated first in the present paper, there is a distinct 
approach from the diandrous or prevailing willow type toward 
the poplars, most conspicuously shown in the increased- number 
of stamens but also evidenced in the disc which becomes com- 
pound with several glands and sometimes almost forms a lop- 
sided cup. It is, too, in the polyandrous willows and in those 
diandrous species manifestly most closely related to them that 
we find most of the arborescent species—a habit prevailing 
among the poplars—while most of the willows are shrubs. 
There are recognized in all something like two hundred 
species of willows. They are mostly natives of the north tem- 
perate zone but are not entirely absent from the torrid and south 
temperate zones. 
The willow may be counted one of the most successful of 
present day plants. In few other genera, so compact and homo- 
geneous in respect to their floral characters, is there shown so 
great a variety of adaptations to varied conditions of life. With- 
in this one genus may be found plants all the way from large 
trees to dwarf herbs, affecting habitats from the fertile alluvial 
plain to the barren mountain peak. They grow almost every- 
where but yet there are certain limitations in their habitat. 
Varying from hydrophytes to xerophytes, they are uniformly 
lovers of the sun and never found to any extent in deep forests 
or other shaded situations. In their various habitats their 
vegetative structures undergo wide modifications to accommo- 
date them to their environments. Some species like Salix lucida 
have broad thick leaves, protected from too severe conditions by 
the hard glossy surface. In others like Salix adenophylla the 
same protection is gained by a thick coating of wool on one or 
both surfaces. Ora heavy coat of glaucescence may be devel- 
oped probably to a degree at least for the same purpose. In 
other cases the leaves are so small as to enable them to endure 
the most severe conditions, especially when, as is often the case, 
