THE WILLOWS OF OHIO. 30] 



of its leaves contrasting strongly with the rich green of the upper 

 surface. In some hybrids, however, most noteworthily Salix 

 Candida x. S. petiolaris the resemblance is so close as to make it 

 all but impossible to separate the two. But such hybrids usually 

 have a distant scolloped serration derived from 5. petiolaris 

 which is different from any form of 5. humilis. At flowering 

 time there will be no difficulty in separating them. 



Salix humilis var. tristis (Ait.) Dwarf Gray Willow. 



A depauperate form of S. humilis with which it is ci ted 



by many intermediates. It may be described as smaller and 

 hairier throughout. It is quite low (to 6 dm.) with smaller 

 leaves (to 5 cm. long) more strongly gray tomentose, and catkins 

 sometimes scarcely 5 mm. long. This can hardly be regarded as 

 a distinct spi There is not a single constant character by 



which the two differ and what differences there are, are such 

 would lie likely to be caused by differences in environment. 

 h forms should be considered as varieties rather than as 

 spec: 



SERICEAE. 



Swamp shrubs, leaves narrowly elliptic-lanceolate, com- 

 monly tapering to both end rate with blunt cartilaginous 

 teeth to entire, glabrou I aucous, sericeate below when young, 

 generally blackening in drying. Aments bora before the lea-v 

 or sh luncled, scales darkened at the tip, pili 

 capsule led, silvery sericeate at least when young. 



Key. 



F: tm lea-. 



Leaves dull above, silvery silk}' beneath at least until very 



-<ld, ly glaucous. 5. 



Leave shining above, glabrous on both side- i | when 



on you mostly ferruginous, 



quite glai below. 5. /</. 



From l 



Fruiti kins di ile, capsule ovoid-conic, obtu 



'lied u when ripe, hardly I mm. 



long. 

 Fruiting caktin rt peduncled, capsule becorn 



lindric conic, acutish, long pedicelled, nearl) glabi 

 when mature, more than I mm. Ion S. peti 



Plat '-.I 



Typical l-a\ es flo na1 ur draw n in 



with lui id.. 



