< 
1918] SCHNEIDER—SALIX 25 
seen a sterile co-type (Herb. M.). RowLEer’s form is apparently identical with 
that described and figured by Hooker and Arnort, but the flowers of the 
only specimen seen by ROWLEE from Colima (leg. E. Palmer, no. 1193, Janu- 
ary 9 to February 6, 1891; m.; G., W.) possess mostly two glands. It seems 
to me somewhat intermediate between the typical taxifolia and var. micro- 
phylla s. str. and needs further investigation. 
10. S. EXIGUA Nutt., var.—S. exigua Goldman in Contrib. 
U.S. Nat. Herb. 16:320 (Pl. Low. Cal.). 1916. 
S. exigua Nutt. sensu latissimo is a wide spread willow from the North- 
west Territories through the western United States (except along the Pacific 
Coast and the most of California) to Arizona, southern California, and New 
Mexico. In my opinion this species may be divided into several varieties 
which of course seem to be connected by intermediate forms. Having not yet 
finished my study of those forms I am not able to determine ‘the following few 
specimens from Mexico with certainty. 1 can only enumerate them and add a 
few notes. 
There is, first, a specimen from Lower California: Arroyo de Leon, north- 
west slope of the San Pedro Martir Mountains, alt. 950 m., July 4, 1905, 
A. E. Goldman (no. 1200, m.; W.). It can probably be referred to S. exigua, 
var. stenophylla (Rydbg.) Schn., nov. var.,3 but owing to the absence of female 
wers 1 am not sure of its relationship. To the same form seems to belong 
a male specimen from Chihuahua: along the Rio Grande, near Ciudad Juarez, 
1911, E. Stearns (mixed in Herb. N. with a fruiting branch of S. Gooddingit). 
C. G. Pringle’s no. 2 3 from the same state, Bachimba Canyon, May 30, 1885 
(m.; G.), which has been distributed as S. taxifolia, probably represents the 
same form of exigua with early flowers which always look rather different from 
those appearing later in the season on longer, more leafy peduncles. The 
aments are very short, but the material is too insufficient to say more. At 
*’ S. stenophylla Rydberg in Bull. Torr. Bot. Club 28:272. rgor has been described 
from Colorado as “nearest related to S. exigua Nutt.” It is, in my opinion, not a 
800d species, but probably more than “‘an inconstant form” (Ball in Coult. and Nels., 
New Man. Rocky Mt. Bot, 131. 1909), and I am inclined to use this name for what I 
call the southeastern and southern variety of exigua, the typical form of which seems to 
be confined to Nevada (and F che aAtacontcountins of Cablornin) eaatemn0 
2 typical exigua. The var. stenophylla differs chiefly in having folia saepe distinctius 
denticulata (interdum fere ut in S. longifolia), ovaria (vel saltem fructus) longius 
