170 Botanisches Centralblatt. — Beiheft 3. 



the mouutains namely Woodwardia radicans Smith. Tbis growe 

 luxuriantly about the tiny mountain Springs and is larger and 

 more leatbery in texture than wben growing on tbe Atlantic slope 

 of America. 



Arborescent forms are only found as isolated specimens or 

 small clumps on the lower parts of the mountain sides. The forms 

 met with are : Libocedrus decuvrens Torr., Pseudotsuga Douglasii 

 Carr. var. macrocarpa Engelm. and Pinus 'ponderosa Doug. 



Foothill Formation: Like the mountain formation, this is 

 characterized by a scrub growth. The extent of the scrub is not 

 so great and its nature, both as to composition and structure, is 

 decidedly different from that of the mountains. The height of the 

 scrub varies from 0.5 to 2 meters. Its habit is spreading and open — 

 a marked contrast to the more erect and close grown mountain 

 form. The branching is often quite regulär, as in Eriogonum 

 fasciculatum Benth. which has quite a pronounced dichotomy. 

 However, a symmetrical growth is rare. The stems are quite 

 Woody, tough and fibrous. The mountain scrub is social, this is 

 unsocial. As a rule each plant Stands by itself and has more or 

 less clear space about it. Frequently two or three plants cluster 

 together, but these Clusters are always surrounded by a clear area. 



The leaves of the scrub are almost always very small and entire, 

 commonly linear or lanceolate in shape. In texture they are some- 

 what leathery. Hairs are present in almost all cases, and are 

 found on upper as well as under leaf surfaces. Often the hairs 

 are glandulär. The characteristic forms are : Eriogonum fascicu- 

 latum Benth., Ärtemisia californica Lees, Audihertia polystachya 

 Benth., Rhamnus crocea Nutt. and Adenostoma fasciculata H. et A. 

 The last two, as mentioned, are occasionally found in the mountains, 

 but it is in the foothill formation that they are abundant. 



Cactus is a very common feature of the foothills, although it 

 is not equally abundant in all hüls In many cases the cactus 

 raakes up a third or even halt of the scrub. In some instances 

 the hillsides are covered from base to apex with cactus. On these 

 the growth is quite tall, often as much as 2.5 meters high. On 

 these hüls, even herbaceous growth is largely wanting. In Fig. 2 

 we have a hill in which the scrub is about equally divided between 

 Opu7itia, Eriogonum and Ärtemisia. The cactoid growth is composed 

 of two species — Opuntia Engelmanni Salm, and 0. prolifera 

 Engelm. ; the former being twice as common as the latter. 



In the open areas about the individuals of the scrub is a large 

 herbaceous Vegetation. The composition of this varies at different 

 tiraes of the year. In fact there is a quite regulär succession of 

 forms, which begins in the early part of the wet season and con- 

 tinues until the early part of the dry season. From July until 

 the end of the year there is but little change in the herbaceous 

 flora of the foothills. 



Owing tö tiie grayness of the scrub and the small number of 

 herbaceous forms the hills have a dry dead appearance from July 

 until January. Then owing to sprouting of the members of the 



