OAKS OF PACIFIC SLOPE. 165 



9. Quercus densiflora. Hooker and Arnott. 1841. TAN BARK 

 OAK. CHESTNUT OAK. 



This beautiful and curious species resembling a chestnut as much 

 as it does an oak becomes in its headquarters along the streams in Marin 

 County, a tree 40 to 60 feet high, with a trunk 2 to 5 feet in diameter. 

 It ranges from Umpqua Eiver, in northern Oregon, where it is reduced 

 to a small tree but a few feet high (var. echinacea), southward along 

 the Coast Ranges to the Santa Inez Mountains, of southern California ; 

 also, it is found on the west slope of the Sierra Nevada to an elevation 

 of 4,000 feet. Peculiar for its large, long (3 to 4 inches), and erect 

 male flowers, its chestnut -like leaves, and the characters of the acorn 

 cup, the scales of the typical oak being replaced by fleshy awl-shaped 

 spurs, i to | inch long, divergent or recurved. The nut, also, is pecul- 

 iar, being somewhat triangular, looking from above, and it is covered 

 with a dense coat of very short brown hairs. 



Whenever this species attains the dimensions of a tree, small or 

 large, as Dr. Kellogg remarks, "It is the most regular and symmetrical 

 of oaks;" and Prof. Sargent states: "No oak of western America excels 

 the best representatives of this species in massive beauty of outline or in 

 richness of color. In early spring the elongated tender shoots and 

 unfolding leaves, coated with white hairs, appearing like masses of 

 flowers against the dark background of older leaves, light up the conifer- 

 ous forests with a beauty all its own." 



The large proportion of tannin which the bark contains renders it 

 one of the most useful of our trees, and the many cargoes of this bark 

 which are annually loaded at San Francisco from the northern coast 

 regions would make botanists apprehensive of the early extinction of 

 this beautiful tree, Avere it not for the knowledge that the stumps left 

 by the bark Imnter sprout readily from the base so continuing the 

 life of the species in the same manner as that by which the Coast TCed- 

 wood is preserved. 



The tan-bark oak is the only representative in America of a peculiar 

 group of trees found in central and eastern Asia, in which are combined 

 the characters of the oak and chestnut; and from this circumstance it 

 suggests, first, a common origin long ago, in the Arctic region per- 

 haps, from whence the two forms have widely diverged; and, second, 

 a lower formative state of the line of development before it became a 

 fully-equipped oak. This species is one of the most interesting inhab- 

 itants of the forests of the United States. 



The group of chestnut-like oaks to which this species belongs was 

 erected into a sub-genus by Prof. Oersted, and named Pasania* 



*The separation of this group of trees from the genus Quercnx by Oersted, is but 

 in accordance with the progress of botanical science which divides and subdivides, if 



