THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 21 



part of its undergrowth. The grounds upon which the formations 

 have been distinguished, and their range, composition, and structure, 

 will be given here. Discussion of their relations to climate and to 

 other communities is included in other chapters. 



The broad-sclerophyll forest formation is dominated by trees, 

 mainly sclerophyllous evergreens, but including a number of decid- 

 uous species (30.8 per cent). It is typically climax, but in this phase 

 its extent is limited. It is successional where its range overlaps the 

 ranges of the conifer formations, and postclimax in its overlap with 

 the climax chaparral. 



The chaparral formation is made up of shrubs, the great majority 

 being sclerophyllous evergreens. Its climax and successional phases 

 are both of great importance. The latter is related developmentally 

 to the conifer climaxes and is almost totally distinct floristically from 

 the climax phase. 



THE BROAD-SCLEROPHYLL FOREST FORMATION. 



This formation ranges from southern Oregon southward through 

 the coast mountains and Sierra foothills into Lower California, 

 reaching its limit probably in the region of Mount San Pedro Martir. 

 Nowhere, so far as I am aware, does it dominate the country as a 

 conifer forest, for instance, commonly does. It occurs rather in 

 discontinuous patches, which may, however, be of considerable 

 extent. These alternate in the main with patches of chaparral of 

 the type which I have designated as climax. Northward the forest 

 is the more important of the two, especially in the Coast Ranges, 

 while southward the chaparral becomes more and more preponderant. 

 In the north there is overlap also with the ranges of the Sequoia 

 sempervirens and the Pseudotsuga associations of the Pacific conifer 

 formation, and in the Sierras with the formations of the conifer 

 forest region. 



The number of dominant species is not large. In the following 

 list a single asterisk indicates importance also in the conifer forest 

 chaparral; and two asterisks, in both that and the climax chaparral. 



Sclerophylls. 



Myrica californica. Quercus chrysolepis. Pasania densiflora.* 



Castanopsis chrysophylla.* engelmanni. Umbellularia californica. 



Quercus agrifolia. wislizeni.** Arbutus menziesii. 



Deciduous. 

 Quercus kelloggii.* Acer macrophyllum Aesculus californica 



lobata 



Several associations occur, easily recognized because of their 

 relative constancy and wide distribution. Many individual localities 

 would fit into none of them, and therefore in a minute study numerous 

 transitional units might be described. 



