406 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



16. CERCOCARPUS. Mountain-mahogany 



Shrubs or small trees; leaves simple, fascicled, with thickish, entire 

 or dentate blades, these linear to obovate, often prominently veined 

 beneath; flowers solitary or in small fascicles, inconspicuous, with 

 small yellowish sepals and no petals; stamens numerous; hypanthium 

 sheathlike in fruit, enclosing the slender villous achene, the long, 

 persistent, plumose style exserted. 



The plants are sometimes known locally as "deerbrowse," and 

 certain species are important elements of the chaparral in central and 

 southern Arizona, useful in protecting the soil against erosion and 

 affording excellent browse for cattle, sheep, and goats, as well as for 

 deer. Cases have been reported of hydrocyanic-acid poisoning of 

 animals eating the leaves of C. montanus. The Hopi Indians are 

 reported to use the bark of one species to dye leather red brown. 

 The wood is hard and that of some species was used by the Indians for 

 making digging sticks and is occasionally used for making tool handles. 

 The sharp-pointed basal end of the achene and the corkscrewlike tail 

 enable it to penetrate the ground, as in Stipa and Erodium. 



Key to the species 



1. Leaves evergreen, the blades coriaceous, resinous, linear or elliptic, acute at 



both ends, entire, the lateral veins not very prominent beneath (2). 



2. Margins of the blades slightly to rather strongly revolute but with much 



of the lower surface exposed; blades elliptic, 10 to 30 mm. long, 5 to 10 



mm. wide; style in fruit 4 to 7 cm. long 1. C. ledifolius. 



2. Margins of the blades very strongly revolute, with little of the lower surface 



exposed except the midvein; blades narrowly linear, 5 to 15 mm. long; 



style in fruit 2.5 to 5 cm. long 2. C. intricatus. 



1. Leaves deciduous, the blades often thickish but scarcely coriaceous, not 

 noticeably resinous, obovate-cuneate or oblanceolate, rounded or truncate 

 at apex, flat or slightly revolute, usually dentate at least at apex, the lateral 

 veins very prominent beneath (3). 



3. Blades entire or toothed only at or very near the apex, commonly oblanceo- 



late or spatulate, thickish 3. C. brevlflortjs. 



3. Blades toothed well below the apex (4). 



4. Leaf blades thickish, finely dentate with triangular teeth, mostly obovate, 

 commonly 2 to 3 times as long as wide, pale green or grayish beneath. 



4. C. BETULOIDES. 



4. Leaf blades thin, coarsely dentate with ovate teeth, broadly obovate, 

 commonly less than twice as long as wide, white or whitish beneath. 



5. C. MONTANUS. 



1. Cercocarpus ledifolius Nutt. ex Torr. and Gray, PL North Amer. 



1: 427. 1840. 



Both rims of the Grand Canyon, Coconino County (Thornber 8515, 

 Loomis 6926), April. Montana to Washington, south to Colorado, 

 northern Arizona, and California. 



Curlleaf mountain-mahogany. Loomis reports that the plants 

 observed by him were treelike, widely branching, about 4.5 m. high 

 and 0.6 m. in trunk diameter. A height of 6 m. (20 feet), in Grand 

 Canyon National Park, has been reported. 



2. Cercocarpus intricatus S. Wats., Amer. Acad. Arts and Sci. Proc. 



10: 346. 1875. 



Navajo and Coconino Counties, especially common in and near the 

 Grand Canyon, 3,000 to 7,200 feet. Utah, Nevada, and northern 

 Arizona. 



Littleleaf mountain-mahogany. A much-branched shrub, up to 

 about 2.5 m. (8 feet) high. The typical form, with young branches 



