NOTES ON AMERICAN WILLOWS. Ill 



A CONSPECTUS OF AMERICAN SPECIES AND VARIETIES OF 

 SECTIONS RETICULATAE, HERBACEAE, OV.\LIFOLIAE, 



AND GLAUCAE 



Camillo Schneider 



In this third article, as I said in my first paper,' a key will be given 

 containing the species treated in the first two papers, and also those 

 of the sections Reticulatae and Herbaceae (Retusae), together 

 with a few other species the systematic position of which is not yet 

 fully understood, but which are best placed near one of these groups. 

 I have tried to prepare two separate keys for the determination of 

 the male and female plants as I did in "Conspectus analyticus 

 Salicum Asiae orientalis Himalayaeque " in Sargent, PI. Wils. 

 3:73. 1916. Typical complete specimens are not always at hand, 

 and without them even such a good key as that given by Coville 

 (in Proc. Wash. Acad. Sci. 3:300. 1901) to the Alaskan willows is 

 insufficient to determine species. To make a key to the sections 

 only proves likewise of little value owing to the great difficulty of 

 exact limitation of the groups, as I shall explain later, 



Clavis specierum 



I. SECUNDUM SPECIMINA FEMINEA 



A. Ovaria (pedicelHs inclusis) etiam juveniha glaberrima. 

 I. FoHa utrinque concoloria, viridia et stomatifera, minima vel 

 parva; amenta serotina, vulgo paucifiora; bracteae pl.m. 

 concolores, flavescentes vel violascentes, vix vel sparse brevi- 

 pilosae; fruticuli minimi prostrati (sed vide 7. S. Peasei). 

 Folia semper crenato-dentata, utrinque tenuiter reticulata, 

 anni praeteriti nunquam persistentia. 



Ramuli floriferi tenuissimi, breves, fere semper bifoliati; 



bracteae flavescentes, sparse pilosae 8. 5. herbacea 



Ramuli floriferi crassiores, longiores, 2-4-foliati; bractae 



fuscescentes, albido-pilosae 7. S. Peasei 



'Box. G.\z. 66:118. 1918. 

 27] [Botanical Gazette, vol. 67 



