38 American Midland Naturalist Monograph No. 4 



As a group the willows are very easily recognized, although it is often 

 difficult to distinguish between many of the species. The leaves, which are 

 borne alternately, usually have at their base a pair of small leaf-like structures 

 called stipules. A characteristic bitter taste of the stems is due to tannin and 

 other bitter principles contained in the bark. The flowers, without petals, are 

 borne in the axils of tiny scales or bracts in dense oblong clusters or catkins 

 which are popularly called pussy willows, the male or pollen-bearing catkins 

 and female or seed-producing catkins occurring on separate plants. The 

 color and hairiness of the scales of the catkins are important in the identifica- 

 tion of the species. The fruits are tiny capsules which split down the sides 

 to free cottony seeds. 



Willows are extremely important along streams where the roots help in 

 binding the soil and protecting the banks from erosion. The herbage fur- 

 nishes valuable browse for animals and the bark is an important source of 

 food for beaver and other animals. Growth is very rapid and recovery quick 

 after the twigs are eaten off. The tough slender stems, which are very 

 flexible, were used for many purposes by the Indians, especially for basket- 

 making. In Europe willows are often grown for making baskets and wicker 

 furniture. A fiber obtained from the bark has been used as cordage. 



Field Guide to the SpeciesO 



A. Low, prostrate plants less than 6 inches high. 



Leaves '/4 inch long or less; capsules smooth; occurs in Yellowstone National Park 



1 . 5. Dodgeana. 



Leaves mostly more than '/^ inch long; capsules hairy. 



Leaves egg-shaped or elliptic to reverse-egg-shaped or roundish, bright green 

 above. 

 Dwarf creeping shrub; leaves 1/3 to J/2 inch long, whitish below; scales 



yellowish; styles very short or none 2. 5. nivalis. 



Plants more or less prostrate, or up to 3 feet high or more; leaves J/2 to 2 

 mches long, pale below or sometimes whitish ; scales dark brown ; 



style 1 mm. or more long 39. 5. planifolia. 



Leaves narrowly elliptic to reverse-egg-shaped, dull green above; scales brown- 

 ish; styles 1 mm. or more long. 



Leaves 1/3 to I inch long, hairy on the margins, paler or whitish below 



3. 5. petrophila. 



Leaves J/4 to J/2 inch long, smooth and green below 4. S. cascadensis. 



B. Erect shrubs more than 6 inches high. 



1. Leaves mosil'}; linear to narrowly lance-shaped, mostly more than 

 4 to 5 times longer than wide. 



Scales of catkins yellowish, soon falling; leaves all narrow, green on both sides or 

 sometimes whitish below. 



Leaves and leaf-stalks not glandular; stamens 2. 



Capsules not hairy or thinly hairy; leaves 1 J/2 to 6 inches long, smooth or 

 hairy. 



'• Throughout the section on willows the millimeter scale has been used to indicate 

 very small measurements less than 1/12 of an inch. 



