266 OHIO STATE ACADEMY OF SCIENCE. 



Key Based on Carpellate Aments.* 



1. Flowers appearing in pussies before the leaves, bracts small 



or absent. 2. 

 1. Aments and leaves unfolding together, bracts mostly 

 large. 11. 

 2. Capsules glabrous from a wooly rachis, inner membrane 



of bud scale growing out beyond the outer. 3. 

 2. Capsules silky till after breaking open, bud scale not as 

 above. 5. 

 3. Capsules turning brown when ripe, 10 mm. long, aments 

 lax, bracts glabrous and glaucous in fruit. 



5. glaucophylla. 

 3. Capsules remaining green, less than 10 mm. long, bracts 

 green on both sides. 4. 

 4. Bracts narrow, obscurely serrate or entire, aments be- 

 coming rather lax, leaves becoming glabrous above. 



5. cordata. 

 4. Bracts broad, prominently glandular, aments dense, 

 leaves becoming densely tomentose above ; north- 

 ern. 5. adenophylla. 

 5. Style very long and slender, rose red at anthesis, conspicu- 

 ous, capsule snowy white; leaves tomentose; dwarf 

 shrub ; northern. S. Candida. 

 5. Style less than half as long as ovulary, leaves glabrous 

 above. 6. 

 6. Capsules short conic. 7. 

 6. Capsules long conic. 8. 

 7. Aments long, 35 mm. or more, very dense, often opposite, 

 capsules large, strictly sessile, carpellate plant rare. 



5. purpurea. 

 7. Aments short, 30 mm. or less, moderately dense, not oppo- 

 site, capsules small, short pedicelled. S. sericea. 

 8. Capsules short pedicelled. 9. 

 8. Capsules long pedicelled; northern. 10. 



*The fruiting aments of our willows are quite distinctive and though 

 the differences between the species are not always easy to describe, they 

 are constant and easily learned, so that with fruiting specimens we should 

 have a minimum difficulty in determination. But in flower they are by no 

 means so easy to determine. The ovularies are all very much alike and 

 seem not to develop character until filled out. In fruit too, the leaves 

 of most specimens are present and help greatly. 



The greatest need of caution in using the key is to be sure that the 

 descriptions of capsules are not applied to younger stages which are more 

 slender with shorter pedicels. It will also be found difficult to use the key 

 after the capsules have burst. The leaves referred to are those pres- 

 ent at flowering and fruiting time. They mav or mav not be similar to 

 the mature leaves of the species. 



