June, 1901] 



Griggs ^Vernation of Salix 



126 



this backward turning is merely a character of the mature leaf 

 manifesting itself in the bud it is evident that there is here no re- 

 volute vernation but that it is really imbricate. 



The other buds examined vary from the form represented in 

 figure 1 where the whole interior of the bud is taken up with the 

 closely packed leaves, to that shown in figure 2 where there are a 

 few leaves with a great deal of wool. 



Species like Salix fragilis L. whose leaves are glabrous when 

 they unfold have buds like the former while species like Salix dis- 

 color Muhl., with leaves excessively wooly when they unfold, are 

 like the latter. As there are all intergi'adations between these two 

 kinds of leaves, there is naturally a series of buds between these two 

 as extremes. While further investigation is necessary before we 

 would be warranted in declaring that the vernation of the whole 

 genus is imbricate ; yet the fact that specimens of thirty -four species 

 and varieties, taken from thirteen of the nineteen sections given by 

 Andersson in DeCandolle's prodromus,\have their leaves imbricated 

 in the buds would seem to establish a presumption in favor of such 

 a view. 



The buds examined were soaked in 10 % alcohol and free-hand 

 sections^ cut and mounted in balsam. Onaccoftint of scarcity of 

 material, the buds of several species were not Sectioned but dissected 

 on the growing plant. Such are marked | with an asterisk (*). As 

 far as possible living material was taken, mostly from native plants. 

 Those species not native were studied from speciineils growing in 



