THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 93 



30.8 per cent, the conifer forest chaparral, with 29 dominants, has 

 12 deciduous, or 41.4 per cent. Of these 12, 7 are not characteristic- 

 ally Californian, ranging far beyond the boundaries of the State. 

 It is thus evident that the most characteristically Californian com- 

 munity is made up entirely of evergreens, so far as its dominants are 

 concerned, and that the community which has the greatest proportion 

 of deciduous species is also the least characteristically Californian. 

 Further discussion of the leaf will be confined to the evergreen species, 

 or, in other words, to the broad-sclerophylls. 



EXTERNAL CHARACTERS. 



Compound leaves. — Of the 74 broad-sclerophyll species, only 2 

 have compound leaves. These are Berberis pinnata and Xylothermia 

 montana. The leaves of the first are pinnate, with 5 to 9 leaflets, 

 and the second palmate, ordinarily with 3 leaflets. In the measure- 

 ments to follow, the individual leaflet of these species has been taken 

 as the unit. 



Form. — Lobing is still rarer. Fremontodendron californicum is 

 the only species, and even in this many of the leaves are unlobed. 

 In shape there is great uniformity. Of the 71 species which are 

 neither compound nor lobed, 54 are of the oval type, ranging from 

 orbicular through elliptic to ovate, the great majority being elliptic. 

 Ten are distinctly obovate, 5 are lanceolate or oblanceolate, and 2 

 (genus Adenostoma) are linear and terete. Adenostoma fasciculatum, 

 the most important single species, is not a ftroad-sclerophyll at all, 

 but, as already suggested, this is hardly sufficient ground for dis- 

 carding for the whole type that very satisfactory appellation. 



Size. — It is well known that leaf-size is a fairly trustworthy measure 

 of habitat, especially of the moisture element. Raunkiar has pro- 

 posed an ecological classification of plants upon the basis of this 

 character, which has been recently brought to our attention in the 

 translation by Fuller and Bakke (31). He has established several 

 size-classes based upon the surface area, the upper limits of which are 

 as follows: 



«9. mm. 



1. Leptophyll 25 



2. Nanophyll (9 by 25 sq. mm.) 225 



3. Microphyll (9' by 25 sq. mm.) 2,025 



4. Mesophyll (9' by 25 sq. mm.) 18,225 



5. Macrophyll (9* by 25 sq. mm.) 164,025 



6. Megaphyll 



Some other delimitation of the classes would have served much 

 better for the broad-sclerophylls of California, since most of the 

 leaves seem to group themselves about the division-lines, but for 

 the sake of comparison with other regions it is better to hold to the 

 system that Raunkiar has established. All the leaves to be classified 

 here come under the first four classes, and it may be helpful to state 



