SUMMER KEY TO THE SPECIES OF SALIX* 



a. Leaf-petioles without glands. 



b. Leaves 1 A-Y$ inch broad; petioles broad and flat 



S. nigra, p. 37. 



bb. Leaves 24-i}4 inches broad; petioles slender and terete.. 



5". amygdaloidcs, p. 39. 



aa. Leaf-petioles glandular above. 



b. Leaves /4-//i ich broad, sharp-serrate; tree with weeping 



habit S. babylonica, p. 43. 



bb. Leaves l / 2 -i l /2 inches broad, blunt-serrate; tree with up- 

 right habit S. fragilis, p. 41. 



WINTER KEY TO THE SPECIES OF SALIX 



The classification of the Willows is a task for the specialist, 

 even when leaves and both staminate and pistillate flowers are 

 obtainable. It is impracticable for the novice to attempt the deter- 

 mination of species of Salix with winter characters alone. Con- 

 sequently the usual winter key is omitted. 



*It is not intended that this key shall serve as a means of 

 identification of any species of Sali.r found in Michigan, but it 

 is added simply to give a ready comparison of the four species 

 which are described. 



34 



