248 Rowlee : North American Willows 



all of Nuttall's species, a gratifying result which the writer did not 

 anticipate when the work of comparison was under way. This 

 necessitates the restriction of S. fluviatilis Nutt. to its original use 

 as a name for the forms with long-pedicelled pistils. It is ap- 

 parent that recent authors have interchanged the names 5. argo- 

 phylla and S. sessilifolia, thereby adding to the confusion of the 

 Californian species. 5. brachycarpa Nutt., usually referred as a 

 synonym to some species of this group, does not belong here at 

 all but is 5. stricta (Anders.) Rydberg, S. desertorum Rich, of re- 

 cent authors. Since Nuttall's is the oldest name it should stand. 



Synopsis of Species 



■ 



Leaves very small, I cm. long, awl-shaped; amentsoval, I cm. long, gland in staminate 



flower one. 



t. S. nricropkylla. 



Leaves larger, 2 cm. or more in length ; aments more or less elongated, glands in stami- 

 nate flower two or more (except in S. Thurberi}. 

 Capsules hairy, at least when young. 



Aments densely flowered, species of the Pacific slope. 

 Stigma raised on a distinct style. 



Leaves linear-lanceolate, coriaceous ; aments on long leafy peduncles. 

 Aments small, 1-2 cm. in length and few-flowered, usually in 

 threes at the ends of the branches. 2, S, taxifolia. 



• Aments medium size, 3 cm. or more in length, cylindrical, many- 



flowered, usually solitary at the ends of the branches. 



3. £ Paris hiana. 

 Leaves elliptical or elliptical- lanceolate, membranous ; aments larger 



on shorter peduncle. 

 Leaves densely silky hairy throughout ; aments medium size, 2-5 

 cm. long. 4. S. macrostachya. 



Leaves not densely silky ; aments large, 6-8 cm. long. 



5. S. se^sil* folia. 

 Stigmas sessile ; leaves entire or nearly so, stipules wanting. 



6. S. argophylla. 

 Aments loosely flowered, species east of the Rocky Mountains. 



1 



Capsules silvery white with appressed silky hairs. 7. S. Thurberi. 



Capsules thinly pubescent. 8. S. interior. 



Capsules strictly glabrous. 



Leaves entire or spinulose-denticulate, coriaceous. 



Capsules pedicelled ; leaves denticulate. 9. S. flmiatilis. 



Capsules sessile ; leaves entire. 10. S. exigua. 



Leaves closely and prominently serrate, not coriaceous. 



Leaves distinctly glaucous and prominently veiny beneath. 



Leaves not distinctly glaucous nor veiny beneath. 



II. S. tJielanopsis. 



12. S. Bolanderiana. 



