215. QUERCUS EXGELMANXI ENGELMANX OAK. 37 



generally short, as it dmdes within a few feet of the ground into two 

 or a few large limbs, and then develops a wide rounded symmetrical 

 top generally depressed in the center. With its dense blue-green 

 foliage and its branches generally festooned with the interesting gray- 

 green lichen (Ramalia reticulata), so abundant in the region in which 

 it grow?, this is indeed a beautiful tree. The bark of trunk is gener- 

 ally of a pale-gray color, but darker on trees in shaded valleys. It 

 becomes fissured with age into shallow ridges and exfoliates in long 

 friable scales. 



HABITAT. The Blue Oak is scattered over the foot-hills and slopes 

 of central California, never seeming to crowd each other sufficiently 

 to interfere with characteristic habit of growth, and in company with 

 Q. lobata and agrifolia imparting to many a landscape the appear- 

 ance of beautiful parks and large open apple orchards. It ranges as 

 far north as the upper valley of the Sacramento river and southward 

 to the Mohave desert, ascending the western slopes of the Sierra 

 Nevada mountains to about 4,000 ft. altitude, and probably attaining 

 its largest dimensions in the Salinas valley. 



PHYSICAL PROPERTIES. Wood very heavy, hard and strong, with 

 numerous and (for an oak) rather small medullary rays, and owing to 

 quite even distribution of open ducts the annual rings are not well 

 defined in these two features quite different from most of the oaks. 

 The wood is of a dark-brown color and sap-wood yellowish white. 

 Specific Gravity, 0.8928; Percentage of Ash, 0.84; Relative Approxi- 

 mate Fuel Value, 0.8853; Coefficient of Elasticity, 77166; Modulus, 

 of Rupture, 993; Resistance to Longitudinal Pressure, 567; Resist- 

 ance to Indentation, 374; Weight of a Cuoic Foot in Pounds, 55.64. 



USES. The short trunks of this tree are poorly adapted to com- 

 mercial purposes, excepting for fuel;, for which they are excellent. 



215 QUERCUS ENGELMANNI, GREENE. 

 , ENGELMANN OAK. 



Ger., Eiche von Eivjelnmnn ; Fr., Chene d^Engelmann ; Sp., Roble 



de Engelmann. 



SPECIFIC CHARACTERS: Leaves pejsistent until the new leaves of the follow- 

 ing spring, oblong to obovate. ^ in. long, mostly rounded or cordate at base and 

 obtuse or rounded at apex, and with entire (though occasionally with coarsely 

 serrate-dentate) margins, ruf ous-tomentose at first but finally glabrous, blue-green 

 above, paler and sometimes puberulous beneath, thick coriaceous and with rather 

 obscure veinlets; petioles about ^ in. lonsr; leaf -buds about ^ in. long, puberulous; 

 branchlets stout, hoary pubescent during the first year. Flowers appear in early 

 spring, the staminate in slender aments, f in length; calyx light yellow, pilose 

 outside; stamens with slender filaments and exserted anthers; pistillate flowers 



