260 BOTANICAL GAZETTE [OCTOBER 
into Lower California. This area is characterized by the presence 
of forms from the Pacific coast, the Californian and the Sonoran 
areas, as these are laid down by Dr. Merriam. The same con- 
clusion is reached by a consideration of the floral distribution of 
the region. In its upper portion genera and species which are 
distinctively of the northern coast flora are both numerous and 
abundant; passing southward these become fewer and rarer. 
Many entirely fail to reach our part of this area, while others, 
like Myrica Californica and Arbutus Menziesii, are here local 
varieties. On the other hand, distinctively Sonoran plants, such 
as the yuccas and the Cactaceae, common in the south, drop 
out as one passes northward. At no point can a dividing line 
be drawn; and there is an important element of the flora, in con- 
siderable part connecting it with that of the Californian area, 
which is about equally abundant throughout the whole region. 
The table last given, of genera exclusively Cismontane, shows 
but a weak Sonoran element, and from it one might infer that. 
the flora of this area was overwhelmingly Coastal and Californian. 
But the table exhibits only half the truth, since the Sonoran 
element is represented mostly by genera which the Cismontane 
area shares with the Desert. Indeed, so prevalent is this element 
that it gives the flora an aspect decidedly Sonoran. The abun- 
dance of yuccas and the large development of the Cactaceae 
have been mentioned already. Some other desert plants that 
pass into the Cismontane are Prosopis julifiora, Bebbia juncea, 
Philibertia linearis, Chilopsis saligna, Abronia villosa, Encelia 
farinosa, E. Californica, Viguiera deltoidea var., etc. Omitting 
species that merely enter the respective borders of one area or 
the other through the different passes, there are over forty 
species of the Desert fairly frequent throughout the Cismontane, 
or a considerable part of it; on the other hand, hardly a single 
distinctively Cismontane species more than enters the confines 
of the Desert. 
A small group of plants, which have entered directly from 
Lower California, inhabit a narrow strip along the coast. Some 
barely pass our borders; few penetrate very far within it, and 
75 MERRIAM, J. HarT, N. Am. Fauna 3, map §. 
