1918] SCHNEIDER—AMERICAN WILLOWS 345 
“S. cordifolia americana, quam olim S. Pyrenaicae forma credidimus, 
vix a formis foliis tenuioribus nigricantibus S. villosae est distin- 
guenda.” This is a most curious statement, because he never 
referred S. cordifolia (or part of it) to S. pyrenaica, but he did pro- 
pose (1858) aS. alpestris a pyrenaica besides his alpestris americana. 
Furthermore, under S. glaucops var. villosa ANDERSSON (1868) 
quotes “S. cordifolia Hook. Fl. Boreal.-amer. p. 152 p.p. (non 
Pursh).” These statements convey the impression that ANDERS- 
SON was unable to interpret properly HOOKER’s species. 
RYDBERG (1899) proposed the new name S. Waghornei for S. 
cordifolia Hook., not Pursh, without explaining why both are not 
identical, and without mentioning the fact that Hooker in his cor- 
difolia also included specimens of DRuMMOND from the “high parts 
of the Rocky Mountains.” He says “Type in Herb. Torrey (‘FI. 
Am. Bor.’),’’ which is a poor and almost valueless fragment con- 
sisting of one piece with a few remnants of fruits and another small 
one with undeveloped rather abnormal male catkins. The leaves 
of both have stomata in the upper epidermis, and the specimen 
looks more like a hybrid between S. cordifolia and S. anglorum than 
like S. cordifolia, which is certainly not identical with this ‘type.”’ 
I am inclined therefore to use the name S. Waghornei for this sup- 
posed hybrid. 
RYDBERG (1899) proposed 2 more species: S. aira and S. labra- 
dorica. Judging by the type before me, S. aéra represents nothing 
but a form of S. cordifolia, of which I shall speak later, while S. 
labradorica is still a rather uncertain form because the female type 
(Waghorn’s no. 36, 1892) as well as the male syntype (Waghorn’s 
no. 31, 1892) differ from typical S. cordifolia by the presence of 
stomata in the upper leaf epidermis. The plants are too young to 
afford sufficient characters to recognize their real affinity. Accord- 
ing to RvpBEro’s key, S. labradorica differs from the other species 
by its broadly ovate leaves “with white, villous almost permanent 
hairs, spreading in all directions,” while in S. Waghornei and S. atra 
“the leaves are somewhat hairy when young, but the long white 
hairs are, as in S. glauca, appressed and parallel to the midrib.” 
This kind of silky pubescence may be seen on the lower surface of 
the first (lowermost) leaves of almost all the forms in question, 
