254 Dr. R. Brown on some new or little-known 



It is often loaded with fruit when not more than three or four 

 leet high, though it will reach the height of more than forty- 

 feet. Mr. Bolander, a most observant Californian botanist, 

 remarks that on river-banks and in exposures close to the 

 coast, where it is almost daily enveloped in fogs, it exhibits a 

 considerable uniformity, and elsewhere it varies infinitely 

 within the type. The figure of Q. oxyadenia^ Torr., in Sit- 

 greave's Report, p. 173, pi. 17, represents the ordinary form 

 of it very well when the acorns are fully developed. How- 

 ever, in the valleys of the interior of Oregon and California 

 (for it is not found north of 43° N. lat.) the shapes of the leaves 

 of one and the same tree are 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 or 

 obliquely sinuate toothed ; teeth very sharply acute, with a 

 broad base, cuspidate-awned," thus agreeing with Kellogg's 

 Q. Morheus^^ while the older branches have much smaller 

 and entire leaves. In Anderson's Valley I saw several trees 

 whose entire foliage agreed admirably with KeUogg's. Had 

 I not seen that tree on the shore of Borax Lake exhibiting 

 both forms, I should have been inclined to call it a good spe- 

 cies. The cups of the acorns of both ti-ees 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 we have not been 

 able to find good reliable characters. There are transitions in 

 all parts, even in 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 : but 

 this is not so ; just the very extremes may be found in one 

 and the same group. On dry gravelly hill-sides in the inte- 

 rior tliis tree presents still another form, QAVisHzem^^n^hn.^ 

 The acorns ripen annually, and differ also essentially in shape 

 and size. Soil, climate, and exposure offer in this case 

 no satisfactory explanation for so great a variation in one 

 species J. I am inclined to believe that it must be attributed 

 to some intrinsic peculiarity which would lead certain species 

 both of plants and animals to vary so much from their typical 

 form as to almost lead one to believe that we see therein the 

 species struggling to break off and establish new forms or 

 races, allied to but differing specifically from the parent 

 species. 



* Proc. California Acad. Nat. Sciences, vol. ii. p. 36. 

 t DeCandolle's Prodromus, vol. xvi. p. 67. 

 t Proc. Cal. Acad. Nat. Sc. vol. iii. p. 229. 



