46 A FIELD GUIDE IN NATURE-STUDY 



ii Branches ascending 



j Shrubs or low trees less than 20 ft. high 



k Twigs purplish Purple Willow (S. pur pur ea) 



kk Twigs brownish or yellowish 

 / Petioles and stipules glandular 

 m Leaves shiny, green both sur- 

 faces Shining Willow (S. lucida) 

 mm Leaves shiny, pale below 



Autumn Willow (S. serrissima) 

 II Petioles and stipules not glandular 



m Leaves entire, elliptic; 1-3 ft. S. pedicillaris 



mm Leaves more or less toothed 

 n-T Leaves not white below 



o Leaves dull green above S. cordata 



oo Leaves glossy above 



Shiny-leaved Willow (S. glaucophylla) 

 nn Leaves white below 



o Leaves elliptic to ovate, 

 the fine teeth glandular 



Balsam Willow (S. balsamifera) 

 oo Leaves lanceolate to ob- 

 long 

 p Young leaves densely 



silky Silky Willow (S. sericea] 



pp Young leaves only 

 slightly hairy 

 q Leaves lanceolate, 



taper-pointed S. petiolaris 



qq Leaves oblong- 

 lanceolate, acute 



Glaucous Willow (S. discolor] 

 jj Trees 20-70 ft. high 



k- Leaves narrowly lance-shaped, six 



times as long as wide Black Willow (S. nigra) 



kk Leaves broadly lance-shaped, less than 

 six times as long as wide 

 / Pale beneath 



Peach-leaved Willow (S. amygdaloides) 

 II Same green both sides 



Fragile Willow (S. fragilis) 

 gg Leaves persistently hairy, at least below 



