iQig] SARGENT— NORTH AMERICAN TREES 21 1 



sometimes i m. in diameter, a broad head of wide spreading branches, slender 

 branchlets, glabrous or puberulous, and lustrous yellow-green leaves often 

 puberulous early in the season. The bark of the branches and young stems 

 is nearly white and on old trunks it is pale green and slightly divided into 

 broad flat ridges. 



PoPULUS ARizoNiCA var. Jonesii, n. var. — Differing from the 

 t^-pe in the pubescent, not puberulous, young leaves, petioles, and 

 young branchlets. 



Mexico, Valley of Palms, Marcus E. Jones, April 8, 1882 (no. 373, type); 

 valley near Chihuahua, C. G. Pringle, March 31, 1886 (no. 885); Saltillo, C. G. 

 Pringle, June 4, 1888 (no. 2098, with larger leaves and more pubescent branch- 

 lets), C. 5. Sargent, March 1887 (a very large tree with pendulous branches); 

 Valley of Mexico, C. G. Pringle, February 13, 1899 (no. 8019); Pedras Negras, 

 C. S. Sargent, March 21, 1900 (a planted tree). 



Populus Palmeri, n. sp. — Leaves thin, ovate, cuneate or rounded 

 at the broad base, gradually or abruptly contracted at apex into a 

 narrow acuminate entire point, finely serrate with incurved teeth, 

 ciliate on the margins when they unfold, otherwise glabrous, 

 6-10 cm. long and 4.5-8 cm. wide; petioles slender, glabrous, 

 3.5-6 cm. in length. Flowers not seen. Fruit in slender glabrous 

 aments 12-15 cm. long, ovate, obtuse, slightly pitted, puberulous, 

 thin- walled, 4-valved, 6-7 mm. long, the disk deeply lobed, 4-5 mm. 

 in diameter; pedicels slender, 7-9 mm. in length. 



A tree 20-21 m. tall with a straight trunk i m. in diameter, erect, smooth, 

 pale branches forming an open pyramidal head, the lower branches smaller, 

 horizontal or pendulous, and slender, glabrous branchlets hght reddish brown 

 €arly in the season, becoming pale grayish brown in their second year. Bark 

 pale, 5 cm. thick, deeply divided by w^de fissures into narrow ridges. 



In most fertile soil near springs, at the base of high chalk bluffs of Nueces 

 Canyon of the upper Nueces River, Uvalde County, Texas, growing with Salix 

 nigra var. Lindheimerii, Carya pecan, Morus rubra, and Ulmus crassijoUa, E. J. 

 Palmer, April 11 and September 1918 (nos. 13340, 14511). 



In the shape of the leaves and their serration, in the small fruit, and in 

 the remarkably slender branchlets this poplar is so different from all other 

 American species that, although it is stiU very imperfectly known, I venture 

 to describe it. It is the only species seen by Palmer in Uvalde County. 



Populus texana, n. sp. — Leaves thin, glabrous, broadly ovate, 

 truncate at base, gradually narrowed, long-pointed, acuminate at 

 apex, coarsely crenately serrate below the middle, entire above, 



