SALICACEA, SILVA OF NORTH AMERICA. 71 
POPULUS WISLIZENTI. 
Cottonwood. 
PisTILLATE flowers long-pedicellate. Leaves deltoid, abruptly short-pointed, coarsely 
crenulate-serrate, their petioles laterally compressed. 
Populus Wislizeni. Forest Trees N. Am. 10th Census U. S. ix. 175 (excl. 
Populus monilifera, Torrey, Bot. Mex. Bound. Surv. 204 syn.). — Wesmael, Bull. Bot. Soc. Belg. xxvi. 377 (Rev. 
(not Aiton) (1859). Gen. Populus) (in part). — Coulter, U. 8S. Nat. Herb. ii. 
Populus Fremontii, var. (?) Wislizeni, Watson, Am. Jour. 420 (Man. Pl. W. Texas). 
Sci. ser. 3, xv. 136 (1878) ; Proc. Am. Acad. xviii.157.— Populus Fremontii, Sargent, Silua N. Am. ix. 183 (in 
Brewer & Watson, Bot. Cal. ii. 92 (in part). — Sargent, part) (1896). 
A large tree, with wide-spreading branches and pale gray-brown bark deeply divided into broad 
flat ridges, stout light orange-colored glabrous branchlets, and acute lustrous buds. The leaves are 
broadly deltoid, abruptly short-pointed, truncate or sometimes cordate at the broad entire base, coarsely 
and irregularly crenulate-serrate except toward the entire apex, coriaceous, glabrous, yellow-green and 
lustrous on both surfaces, from two inches to two inches and a half long and usually about three inches 
wide, with slender yellow midribs, thin remote primary veins, and conspicuous reticulate veinlets ; they 
are borne on slender glabrous petioles compressed laterally, from an inch and a half to two inches long, 
and bright yellow in the autumn before falling. The stipules are broadly ovate, acute and apiculate or 
acuminate at the apex, scarious, and caducous. The aments appear before the leaves and vary from two 
to four inches in length, with caducous bracts which are scarious, light red, and divided at the apex into 
elongated filiform lobes. The numerous stamens with large oblong anthers and short filaments are 
inserted on a broad oblique disk. The ovary is long-pedicellate, ovate, full and rounded at the apex, 
crowned by three broad crenulate-lobed stigmas raised on the short branches of the style, and inclosed 
nearly to the middle in the cup-shaped disk which is irregularly toothed on the margins and persistent 
under the fruit. The aments of fruit are four or five inches long, with oblong-ovate thick-walled acute 
three or four-valved slightly ridged buff-colored capsules which are about a quarter of an inch long, 
and are borne on slender pedicels from one half to three quarters of an inch in length, and placed rather 
remotely from each other on the slender glabrous rachis. 
Populus Wislizeni is the common Cottonwood of the Rio Grande valley in New Mexico and 
western Texas, and in the adjacent parts of Mexico.1 From the other Cottonwoods it can be easily 
distinguished by the elongated slender pedicels of the pistillate aments which are peculiar to this tree 
and, showing no tendency to become abbreviated, make it desirable to treat it as a species. 
Populus Wislizent was discovered on the upper Rio Grande in July, 1846, by Dr. F. A. Wis- 
lizenus.” 
1 Speci of a Cott d collected by Miss Alice Eastwood Utah, although beyond its usual range, appear to belong to this 
in July, 1895, on Recapture Creek, San Juan County, soutk species (Eastwood, Proc. Cal. Acad. ser. 2, vi. 325). 
2 See vi. 94. 
