THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 95 



more, there is a very decided maximum in the NMi region, practically 

 half of all being in this class. Species with very small leaves are 

 scarce, though it must not be forgotten that Adenostoma fasciculatum, 

 most important of all, is one of these. Considering the vegetation 

 by communities, we find that of 42 important species of the climax 

 chaparral nearly half are of the NMi class, with the rest well dis- 

 tributed on both sides of it. Of 17 species of the conifer forest 

 chaparral, those of class NMi compose nearly one-half, but the 

 others are all of larger classes. Of the 9 broad-sclerophyll forest 

 species, none are smaller than Mi and the maximum lies in the class 

 MiMe. There is thus shown a relation between leaf-size and habitat, 

 the community living in the driest habitat having the largest pro- 

 portion of small leaves. There is also a correlation between size of 

 leaf and size of plant, since the trees of the broad-sclerophyll forest 

 show consistently greater leaf-size than the shrubs of either of the 

 two chaparral communities. 



Attitude. — In the majority of species the leaves lie horizontally, 

 but there is a small group with vertically placed leaves. Certain 

 species of Arctostaphylos are prominent here, especially A. glauca, 

 A. hookeri, and A. viscida. In many others there is a more or less 

 prevalent tendency toward the vertical position. Dendromecon 

 rigidum has leaves that are ordinarily vertical, but, as in many other 

 cases, they are horizontal in the more mesophytic situations. 



Margin. — A majority of the 74 species (58.1 per cent) have entire- 

 margined leaves, although a number of these may show occasional 

 dentation, especially on stump sprouts. 24.3 per cent have leaves 

 that are more or less toothed in the normal fashion; they are serrate, 

 dentate, or crenate. In nearly every case the teeth are shallow. A 

 smaller but conspicuous and characteristic class (17.6 per cent) 

 have notably spiny-toothed leaves that may be aptly described as of 

 the holly type. The resemblance in leaf character between the 

 various species of this group is often striking. This is particularly 

 true of Prunus ilicifolia and Rhamnus crocea, whose leaves are 

 frequently so similar as to require very minute examination to dis- 

 tinguish them. Eight species (10.8 per cent) have leaves with notably 

 revolute edges. This character appears inconstantly in a number of 

 others. 



Pubescence. — Pubescence is not a prominent feature of the broad- 

 sclerophylls. Of the 74 species, 48.7 per cent have more or less 

 pubescent leaves, but in only 17.6 per cent are thej r pubescent on 

 both surfaces, and often the covering is sparse. The leaves with 

 hair-filled cavities are not considered here unless the hairiness is 

 evident to superficial examination. 



Miscellaneous. — Two species, Eriodictyon californicum and Ceano- 

 thus velutinus, have leaves that are varnished and glutinous on the 



