104 



SILVA OF NORTH AMERICA. cupulieer^. 



of an inch long and about a third of an inch wide, hght dull green when fidly grown and dark chestnut- 

 brown or nearly black when ripe, but soon becoming Hght red-brown in drying, with a thin brittle outer 

 coat and an inner coat hned with thick white tomentum, abortive ovules which are sometimes basal and 

 sometimes are scattered irregularly over the side of the seed, and sweet yellow cotyledons ; the cup, 

 which incloses from one third to nearly one half of the nut, is deeply cup-shaped or nearly hemi- 

 spherical, light green and pubescent within, and covered with closely imbricated broadly ovate acute 

 thin and scarious light brown scales clothed with short soft pale pubescence. 



Quercus Emoryi grows on the mountain ranges o£ western Texas, on those of New Mexico and 

 Arizona south of the Colorado plateau, and on those of Nuevo Leon, Chihuahua, and Sonora/ In 

 Texas it is common in the canons and on the southern slopes of the Limpio Mountains, and is the 

 only tree in some of the caiions of the Chisos Mountains.^ It is the most abundant Oak of southern 

 New Mexico and Arizona, forming a large part of the open forests which clothe the mountain-slopes, 

 and extending from the upper limits of the mesa, where it is mingled with Quercus ohlongifolia, nearly 

 to the highest ridges ; often a shrub at these high elevations, it attains its greatest size and beauty 

 in the moister soil of sheltered caiions. 



The wood of Quercus Emoryi is very heavy, although not hard, strong, brittle, and close-grained ; 

 it is dark brown or almost black, with thick bright brown sapwood tinged with red, and contains bands 

 of several rows of small open ducts marking the layers of annual growth and connected by narrow 

 groups of similar ducts parallel to the broad conspicuous medullary rays. The specific gravity of the 

 absolutely dry wood is 0.9263, a cubic foot weighing 57.73 pounds. 



The sweet nuts, called by the Mexicans biotis, are an important article of food for Mexicans and 

 Indians, and are sold in large quantities in the towns of southern Arizona and northern Mexico. 



Quercus Emoryi was discovered on October 15, 1846, in the valley of Pigeon Creek in southern 



New Mexico, by Colonel W. H. Emory,^ while in command of a military reconnaisance from Fort 

 Leavenworth, in Missouri, to San Diego, California. 



One of the most beautiful of North American Oaks in its symmetry of outline and in the rich color 

 of its foliage, Quercus Emoryi forms with Quercus Arizonica the principal part of the open forests 

 which clothe with perennial green the stony sun-baked lower slopes of the mountains of southern 

 Arizona and New Mexico. 



1 Pringle, Garden and Forest, i. 142 ; iii. 338. s See iv. 60. 



2 Havard, Proc. U. S. Nat. Mus. viii, 505. 



EXPLANATION OF THE PLATE. 



Plate CCCXCVII. Quercus Emoryi. 



1. A flowering branch, natural size. 



2. A staminate flower, enlarged. 



3. A pistillate flower, enlarged. 



4. A fruiting branch, natural size. 



5. Sections of a pericarp showing the tomentum on the inner 



surface, enlarged. 



6. A seed with basal, abortive ovules, natural size. 



7. End of a branch, the leaves removed, showing winter-buds, 



natural size. 



