CUPULIFERJE. 



SILVA OF NORTE AMERICA. 



79 



QUERCUS DOUGLASII. 



Blue Oak. Mountain White Oak 



Leaves oblong, lobed, spinescent or entire, blue-green and pubescent. 



Quercus Douglasii, Hooker & Arnott, Bot. Voy. Beechey, 

 391 (1841). —Hooker, Icon. iv. t. 382, 383. — Bentham, 

 PL Hartweg. 337 ; Bot Voy. Sulphur^ 55. — Nuttall, 

 Sylvaj i. 10, t. 4. — Dietrich, Syn, v. 311. — Torrey, 

 Pacific R. R. Rep. v. 365 ; Bot. Wilkes Explor. Exped. 

 462. — A. de Candolle, Prodr. xvi. pt. ii. 23. — Bolander, 



f . 4, 5 ; Man. Bot. Bay Region^ 302. — Mayr, Wald. 

 Nordam. 264, t. 2, 5- — Dippel, Handb. Laicbholzk. 

 ii. 76, f. 30. — Koehne, Deutsche Dendr. 128. — Merriam, 

 North American Fauna^ No. 7, 333 {Death Valley 

 Exped. ii.). — Coville, Co7itrib. U. S. Nat. Herb. iv. 196 

 (Bot. Death Valley Exped.) . 



« ■ 



Proc. CaL Acad. iii. 230. — Orsted, Vidensk.3fedd.fra Quercus Ransomi, Kellogg, Proc. CaL Acad. i. 25 



(1855). 



Mary K. Curran, Btdl. Cal. Acad. i. 146. 



nat. For. Kjobenh. 66 ; Liebmann Chenes Am. Trop. t. 41, 

 f. 3, 4. — Engelmann, Trans. St. Loitis Acad, iii- 392 ; 

 Brewer & Watson Bot. CaL ii. 95. — Hall, Bot. Gazette^ ? Quercus oblongif olia, R. Brown Campst. Ann, and Mag. 



Brandegee, Zoe^ i. 156- 



ii. 93, 



?/ Califi 



Sar- 



gent, Forest Trees N. Am. 10th Census U. S. ix. 143. 

 Greene, West Am. Oaks, 17, t. 9, f. 1, 2; t- 12, 



Nat. Hist, ser 2, vii. 252 (not Torrey) (1871). 

 Quercus oblongifolia, var. brevilobata, Torrey, Bot 

 Wilkes Explor. Exped. 460 (1874). 



A tree^ rarely eighty or ninety but usually fifty or sixty feet in height, with a trunk three or four 

 feet in diameter and short stout branches which^ spreading nearly at right angles^ form a dense round- 

 topped symmetrical head ; or frequently not more than twenty or thirty feet high^ and sometimes, 

 especially toward the southern limits of its rano^e. 



shrubby in habit. The bark of the trunk is from 



half an inch to an inch in thickness and is generally pale^ although the small scales into which the 

 surface divides are tinged with brown or hght red.^ The branchlets are stout and marked with pale 

 lenticels^ and^ being extremely brittle at the joints^ can be easily broken from the branch ; when they 

 first appear they are coated with short dense hoary tomentum, which continues to cover them more 

 or less thickly during the summer, and in their first winter they are dark gray or reddish brown 

 and tomentose, pubescent^ or puberulous, and in their second or third year grow ashy gray or dark 



b 



The winter-buds are ovate^ obtuse, from an eighth to nearly a quarter of an inch in length 



and are covered with light and rather bright red pubescent 



The 



convolute in the 



bud* and 



oblongs gradually narrowed and wedge-shaped or broad and rounded or subcordate 



^ Miss Alice Eastwood, the curator of the botanical department 



Moiigifolia 



of the California Academy of Sciences, whose unrivaled collection of R. Brown Campst. (not of Torrey), described as a bush three feet 



nia Oaks made in the central and southern parts of the high from the mountains of southern Oregon, which, in the speci- 



CaKfo 



state during the autumn of 1894 has been of great assistance to men without fruit preserved in the herbarium of the Eoyal Botanic 

 me, calls my attention to the fact that Quercus Douglasii has very Garden at Edinburgh, has ovate or oblong-elliptical and nearly entire 



leaves hardly distinguishable in size and shape from those of some 



luercus 



.uercus 



light gray bark on trees growing on exposed hillsides and open 

 plains, and much darker bark on trees in sheltered valleys and 

 arroyos. 



y X ^ ^ 



2 On the foothills and in the valleys of northern and central is more variable than Quercus Douglasii in the size, shape, and den- 

 California the leaves of Quercus Douglasii are perhaps larger and tation of its leaves. They are readily recognized in the field by 

 more commonly lobed than in the southern part of the state, where their blue color, as this is the only blue-leaved Oak of northern 

 they are usually small and often spinescent and entire, but trees 



California 



with 



.his 



with 



the green-leaved Quercus dumosa, and Miss Eastwood suggests that 



common at the south. A specimen collected in Round Valley, natural hybridizing between these trees would account for the 



Mendocino County, in June, 1893, by Mr. G. W. Blankinship, with apparent running together of the two species, which in most of 



thin broadly obovate-oblong leaves entire or slightly notched- their forms are, however, very unlike, 

 toothed at the wide rounded apex, apparently belongs to this spe- 



