235. QUEKCUS HYPOLEUCA WHITE-LEAF OAK. 33 



235. QUERCUS HYPOLEUCA. ENGELM. 



WHITE-LEAF OAK. 



Ger., Weiszblatterige Eiche ; Fr., Chene d feuilles blanches; Sp., 

 Roble de hojas Mancas. 



SPECIFIC CHARACTERS : Leaves lanceolate to oblong- lanceolate, from 2-4 in. 

 long, acute at apex, cuneate, rounded or somewhat cordate at base, with entire 

 revolute or occasionally remotely dentate margin, pubescent at first, at maturity 

 thick and firm, lustrous dark green above and woolly beneath with white tomen- 

 tum, persistent until after the appearance of new leaves ; petioles ^ in. long, 

 pubescent. Flowers open in April, the staminate in slender pale-tomentose 

 aments 3-4 in. long ; calyx pubescent outside, deeply 4 or 5-lobed : stamens 4, 

 exserted, with slender filaments and ovate apiculate anthers ; the pistillate flowers 

 are usually single or in pairs, sessile or short pedunculate ; stigmas dark red, 

 recurved. Fruit acorns maturing the second season, usually solitary and sessile 

 or with short peduncles ; the nut ovoid from \-\ in. long, acute or rounded at the 

 hoary- pubescent apex, dark green and striated at first but drying to a uniform 

 chestnut brown ; shell light tomentose within ; cup turbinate, about one-third 

 enveloping the nut and covered with thin chestnut brown pubescent scales. 



The specific name, hypoleuca, is from Greek words, meaning white beneath. 



This interesting oak occasionally attains the height of 40 or 50 ft. 

 (15 m.) with rather narrow rounded top and trunk 12-15 in. (0.35 m.) 

 in diameter, covered with a dark gray bark deeply fissured into irregu- 

 lar broken ridges which flake off in thick fragments. 



It is one of the most beautiful of our oaks owing to its curious parti- 

 colored foliage, the silvery white under surfaces of its leaves contrasting 

 strongly with the lustrous dark green of the upper surfaces as they are 

 turned up by the wind. In localities where conditions do not favor 

 its fullest development it is found reduced to a shrub. 



HABITAT. The mountains of Texas, New Mexico and Arizona 

 south of the Colorado plateau and southward into Mexico. It is scattered 

 over the mountain slopes among the Chiricahua Pines, Madronas, etc., 

 at an altitude of six or seven thousand feet above tide, seeming to be 

 nowhere very abundant. 



PHYSICAL PROPERTIES. The wood is very heavy, hard, strong, 

 with numerous large medullary rays, and of a very dark brown color 

 with thick brownish white sap-wood. Specific Gravity, 0. 8009 ; Per- 

 centage of Ash, 1.34; Relative Approximate Fuel Value, 0.7902; 

 Coefficient of Elasticity, 94409; Modulus of Rupture, 1113; Resist- 

 ance to Longitudinal Pressure, 293; Resistance to Indentation, 

 272; Weight of a Cubic Foot in Pounds, 49.91. 



USES. The wood, though of valuable properties, is little used 

 owing to sparseness of population and its limited abundance. 



The distinct and beautiful foliage of the tree would seem to insure 

 its popularity for ornamental planting, and it will no doubt when it 

 becomes more generally known be propagated for that purpose. 



