12. _Quercus agrifolia_, Nées. (Live Oak.) Oakland! Banks of Sacramento River! Clear Lake! Russian River Valley! Anderson Valley! Monterey! Foliage extremely variable. On river banks and in expositions close to the coast, where it is almost daily enveloped in fogs, this species exhibits quite a uniformity; the figure of _Quercus oxyadenia_ in Sitgreaves’ Report represents this form of it very well. In the valleys of the interior the shape of the leaves of one and the same tree is very different. Some have entire margins, while others have them pretty deeply dentated, often one side is entire and the other dentate. Some trees occur of which the young shoots have the leaves “coarsely sinuate-toothed, or obliquely sinuate-toothed; teeth very sharply acute with a broad base, cuspidate-awned,” and thus agree with Dr. Kellogg’s _Quercus Morehus_—while the older branches have much smaller and entire leaves. In Anderson Valley I saw several trees whose entire foliage agrees admirably with Dr. Kellogg’s. Had I not seen that tree on the shore of Borax Lake exhibiting both forms, I should be inclined to call it a good species. The cups of the acorns of these trees have the scales long and loosely imbricated, and the acorn is almost entirely immerged; but this is also the case with those of some trees that have a far different foliage. Thus far I have not been able to find good, distinctive, reliable characters. There are transitions in all parts, even on the same tree. As the tree has the habit of growing in groups, one might suppose that trees of one group, at least, should show a uniformity in botanical characters; this is not so: just the very extremes may be found in one and the same group. This phenomenon I observed throughout the whole length of Anderson Valley, a distance of some eighteen miles. On dry gravelly hillsides in the interior this tree presents still another form: _Quercus Wislizeni_, Englm. The acorns ripen annually and differ also essentially in shape and size. Soil, climate, and exposition, offer in this case no satisfactory explanation for so great a variation in one species. Should it not be attributed to intrinsic peculiarities? 13. _Quercus Garryana_, Hook. (White Oak.) On dry easterly hillsides and in valleys on a poor buff-colored clay. Santa Rosa Valley! Clear Lake! Searsville! Anderson Valley! San José Valley! Exposition and soil agree in all these localities.