iQig] SARGENT— NORTH AMERICAN TREES 219 



Rydberg, Bull. Torr. Bot. Club 39:304 (not Newberry). 1912.— 

 C. rugidosa Rydberg, Fl. Rocky Mountains, 207. 1061. 1917.— 

 This tree, which has sometimes been considered the same as the 

 more southern C. reticulata Torrey, can be distinguished from 

 that species by its rather thinner, oblong-ovate, long-acuminate, 

 coarsely serrate leaves, cordate or obliquely cordate at base, 

 glaucescent on the lower surface and glabrous or sparingly pilose 

 on the under side of the midribs and veins, by the slightly pilose 

 petioles, and by the much longer pedicels of the fruit sometimes 

 up to 1.5 cm. in length. The fruit, which has been described 

 as "black or brownish," is light orange-brown on the Oregon and 

 Colorado trees, and is subglobose to ellipsoidal and 7-8 mm. in 

 diameter. 



C. Douglasii is a shrub or a small tree rarely 10 m. high, with rough, red- 

 brown, or in Colorado dark gray bark 2.5 cm. thick and irregularly ridged, 

 glabrous or slightly pilose branchlets, and pubescent and tomentose winter- 

 buds. 



Nowhere common, it is widely distributed on dr>'- ridges and the rocky 

 banks of streams, and occurs in Oregon east of the Cascade Range in the valley 

 of the Deschutes River, on the rocky banks of the Columbia near the Dalles 

 and on Pine Creek, Gilliam County, and in western Washington ranges from 

 the valley of the Columbia in Klickitat County to the rocky banks of Snake 

 River in Whitman County, and to Big Willow Creek, Canyon County, Idaho; 

 it inhabits the western foothills of the Wasatch Mountains of Utah, south- 

 eastern Utah (Grand River Canyon below Moab, Grand County), the southern 

 slope of the Grand Canyon, Arizona {A. Rehder, July 19, 1914, no. 103), "in 

 sand at the mouth of a dr}- canyon one-half mile below Democrat Springs, Kern 

 River," Kern County, California, Mrs. Leo Polkingham, September 1916 (in 

 Herb. Dudley), and on the eastern foothills of the Rocky Mountains of 

 Colorado. 



In the shape of the coarsely serrate leaves and in the long pedicels of the 

 fruit C. Douglasii is related to C. occidentalis var. crassifolia, from which it 

 differs in its thicker leaves with conspicuous reticulate veinlets and usually 

 glaucescent and less pubescent on the lower surface, and in the color of the 

 fruit. In the thick reticulate- venulose leaves rough on the upper surface it 

 resembles C. reticulata. Geographically C. Douglasii is intermediate between 

 C. occidentalis, which in its var. crassifolia reaches northern Idaho, and 

 C. reticulata, which extends northward to the Grand Canyon in Arizona. 



Celtis Lindheimerii K. Koch apud Engelmann, Dendr. 2:434. 

 1872.— C. Helleri Small, Bull. Torr. Bot. Club 24:439. 1897; 



