A STUDY OF THE RELATIONS OF SALIX 
' NIGRA AND SALIX AMYGDALOIDES, TO- 
GETHER WITH THE HYBRIDS ARISING 
FROM THEM AS THESE SPECIES EXHIBIT 
THEMSELVES IN THE VICINITY OF ST. 
LOUIS. 
N. M. Guatretrer, M. D. 
From considerable previous observation having noticed the _ 
difficulty of classifying many of the specimens either with the 
one or the other of the two species named in the subject of 
this paper, I resolved in the early part of the season just 
passed to collect a large number of specimens with the view 
of ascertaining the essential characters of each and thus, 
perhaps, fixing their proper limits. The result of my efforts 
is 182 pressed specimens from as many different plants, taken 
at random as I came across them. These are all numbered 
and tabulated with reference to their various characters. 
I am well aware that any inferences drawn from them have 
only a local significance, but yet deem them not without 
value, nor without some degree of general interest. The 
large number of hybrids in the collection (38 %), has been 
quite a surprise to myself. I found the hybridization to be 
of every possible degree of intermixture or complexity, grad- 
uating by shades from one species to the other. Often at 
first sight, the specimen in hand appears to belong to the 
one or the other, when upon closer inspection one will find 
defection of or addition of one or more important characters 
properly pertaining to the pure form. It is to be understood 
asa matter of course that a certain degree of latitude has to 
be permitted for the usual amount of variation of a species. 
Owing to the strong contrast presented by the parents in 
several important characters there is ordinarily no difficulty 
(97). 
