The bark of this tree is rather thin, whitish, and less coarsely rimose than any other of the Californian oaks. It is always a flat-topped, middle-sized tree, apparently of a very slow, almost stunted, growth. The whitish bark of trunk and branches, the glaucous foliage, and the light-green color of the acorns, which it yields, however, quite sparingly, give this tree, compared with other oaks especially, quite a pale and hoary appearance. Farmers consider the fine-grained wood of this oak very valuable for many farming implements. It ranks highest among our oaks. 14. _Quercus Douglasii_, Hook. (Pale Oak.) Anderson Valley! The general aspect and habit of this tree resembles very much that of _Quercus lobata_, with which it grows in the low, flat portions of Anderson Valley. Its branchlets, however, are short, rigid, and erect, while those of _Qu. lobata_ are mostly drooping. In fall, when laden with acorns, it presents a very striking difference by having its rather pale acorns densely aggregated and clustered at the extremities of the branchlets, resting, as it were, on the dark-green leaves. At a distance it may be mistaken for a full-bearing apple tree. It increases rapidly in number in Anderson Valley from south to north, outnumbering almost every other oak at the lower end of the valley. Its wood ranks next to that of _Quercus Douglasii_. 15. _Quercus lobata_, Nées. (Burr-Oak.) The most common and largest oak in all the valleys of the interior of California. Thus far, I never found it on a hillside. It is this mighty oak, with its peculiar, gracefully-drooping branchlets, that gives character to the landscape of the Californian valleys. It is especially noted for its very long acorns; but they do not always attain that large size, and are never so conspicuously arranged as those of _Qu. Garryana_; they are usually in pairs. It may also be stated that this tree forms, on an average, about the longest trunk of Californian foliaceous trees. The acorns of this species form a principal part of the food of the Indians. On the Coast Range they seem to give, however, preference to those of _Quercus Sonomensis_. The wood ranks next to that of the preceding species. These above-mentioned three species of oaks, belonging to the section of white oaks, are surely distinct. I met with no transitions thus far. They may be distinguished at a distance; every farmer distinguishes them, for there is quite a difference in the quality of the wood. 16. _Quercus Sonomensis_, Benth. (Black Oak.) San Diego!! Anderson Valley! Auburn!