THE WILLOWS OP OHIO. 307 



Key. 



From leaves. 



Leaves glossy above, heavily glaucous below, mostly broad, 

 ascending so as to show their white under sides, glab- 

 rous, northern. S. glaucophylla. 

 Leaves neither glossy nor very glaucous. 



Leaves thick, ovate, with emarginate bases, tomentose 

 on both sides, northern. S. adenophylla. 



Leaves thin, seldom pubescent above, lanceolate, gen- 

 erally distributed. S. cordata. 

 From flowers. 



Bracts strongly glandular, before anthesis very villous, 



aments dense, capsules green, short pedicelled, medium 



sized, northern. 5 adenophylla. 



Bracts not glandular, tomentum quickly evanescent, pedicel 



longer. 



Bracts green, obscurely serrate or entire, capsules green, 



small, medium pedicelled. S. cordata. 



Bracts blackening, glaucescent, capsules large, rostrate, 



becoming brown, long pedicelled, aments lax; 



northern. 5. glaucophylla. 



Salix cordata Muhl. Heart-leaved Willow. 



Salix cordata is the botanist's bugbear. It is one of the 

 most common and most variable species with which we have to 

 deal. Its leaves seem to be under no restraint of heredity and 

 may assume almost any form and any character. I have seen 

 them all the way from linear-lanceolate to orbicular, from sub- 

 glossy to heavily tomentose, from green to glaucous. But var- 

 ious as are the leaf forms they are all united by the flowers and 

 one cannot doubt that they all belong to a single species. 



The separation of the bud scales alluded to above is particu- 

 larly well marked in Salix cordata and in the southern portion of 

 the state or anywhere out of the range of the other species at 

 once differentiates this species from 5. sericea or 5. discolor 

 which it resembles much in early spring. 



Leaves very variable but generally of the lanceolate type, 

 broader or narrower, but widest below the middle, serrations 

 always sharp and usually fine. In leaf it is most likely to be con- 

 fused with 5. discolor and 5. sercicea. From the former it can 



Plate XIII. Salix cordata. 



Leaf showing venation and the two others in the lower portion of 



the plate typical; large leaf from very vigorous water shoot, perhaps indi- 

 cating some affinity with >'. adenophylla; upper narrow leaf from variety 

 angustata; flowers and fruit typical; natural size; capsule enlarged three 

 times. 



