NOTES ON SALIX LONGIPES. 
the intergrading is complex, just as it is between nigra aad 
amygdaloides, or between sericea and cordata, the charac- 
ters of one or the other parent predominating, or constitut- 
ing an almost equal compromise between the two. If the 
specimen in hand approaches nigra, the under surface of 
the leaf will have simply a pale cast, the capsule will be 
smaller, stipules pointed, ament and pedicel shorter, bases of 
the twigs brittle, the tree larger. Since longipes is pecu- 
liarly and intensely glaucous, while nigra is of a brilliant 
green, the gradual stages from one to the other may be, in 
a measure, gauged by the difference in degree of this 
character. 
The late Mr. Bebb had some notions of a close relation 
existing between ‘* Wardi’’ and S. amygqdaloides, as if the 
former were the ‘‘ geographical equivalent’’ of the latter. 
I regard amygdaloides a step farther removed from 
‘*Wardi’’ (longipes) than is nigra. These three willows 
have, however, one peculiar mark or bond of connection, 
so far as I know, limited to this group, in that they all 
have now and then what may be called palmate-veined 
leaves,— small oval or elliptical leaves more or less palmate- 
veined, which when present are found near the base of 
young shoots (Plate 6). 
In the vicinity of St. Louis, we have growing together in 
the same locality longipes, nigra, and amygdaloides. We 
should expect hybrids therefore as follows: nigra X amyg- 
daloides; nigra X longipes; amygdaloides X longipes; 
nigra XK amygdaloides <* longipes. Now, the nigra X 
amygdaloides hybrids are extremely common, amounting 
probably to 50 per cent.of the total black and amygdaloides 
willows. The combination nigra X longipes has already 
been commented upon in this paper. The combination 
longipes X amygdalozdes is identifiable with great difficulty. 
The same of course is true of the combination longipes 
nigra KX amygdaloides. Wowever, I have collected several 
specimens which, I can not doubt, are hybrids of either 
one or the other of these latter forms. The earlier flower- 
7 
