y ac 
270 i Part III. Chapter 3. 
carpa. At 4800 feet (1460 m) elevation, the trees begin to form a forest with 
the following species as the chief components: Adies concolor, Libocedrus 
decurrens, Pinus Coulteri, Pinus ponderosa, Pseudotsuga macrocarpa, Querius 
californica and Quercus chrysolepis. At altitudes of 5400 feet (1650 m) Pinus 
Lambertiana becomes an element in the forest. The forest at the 7000 foot 
(2130 m) contour line consists of Adies concolor, Cercocarpus ledifolius, Funi- 
perus californica and $. occidentalis, Libocedrus decurrens, Pinus Lambertiana, 
Pinus monophylla, Pinus Murrayana and Ouercus chrysolepis. This oak ceases 
with all other species of oaks at 8000 feet (2440 m). From 9500 to 11,700 feet 
(2900—3570 m), which is the highest elevation in the San Bernardino range, 
the forest consists almost wholly of Pinus flexilis and Pinus Murrayana'). 
The mountain flora as the above lists show is essentially a Sierra Ne- 
vadan flora projected southward. Aesculus californica, Quercus Douglasii, | 
O. Wisliseni var. frutescens, Pinus sabiniana, Myrica californica, Arbutus Man- 
ziesii barely enter southern California from the San Joaquin district and hence : 
are forced into a narrow belt between the desert and the mountains oVef 
which they have been unable to pass to a region better adapted to them. 
The following plants form a conspicnous desert element of the flora: Fremontodendron me 
montia) californicum*, Dalea spinosa, Olneya tesota, Prosopis juliflora*, Prosopis pubescens*, Acacı 
Greggii*, Chilopsis saligna (= C. linearis), Yucca baccata*, Yucca brevifolia, Pinus monophyl, N 
Juniperus califormica. Those marked with an asterisk pass to a greater or less extent into the 
intramontane area which is essentially occupied by a Californian flora many plants of which en 
originally derived from the great Sonoran life area. Among the prominent intramontane en 
are: Rhamnus californica, R. californica var. tomentella, Acer macrophyllum, Negundo californieun: 
(= Acer negundo var. californicum), Prunus ilicifolia, Prunus demissa, Cercocarpus parvifolies 
Heteromeles arbutifolia, Sambucus glauca, Umbellularia californica, Juglans rupestris, Querens geh : 
solepis, Quereus agrifolia, Quercus lobata, Alnus rhombifolia, Populus Fremonti var. ir 
Salix laevigata, Salix lasiolepis, Salix lasiandra var. lancifolia, Platanus racemosa. a 
The lower limit of the Sierra Nevada element of the flora Of Dr 
mountains of southern California coiricides with that of Pinus ponderosa. a 
ranges according to exposure from 5000 [1524 m) to 7000 feet (2133 m). & u 
genera given below in the first column are represented by species which be 
long exclusively to the flora of the Sierra Nevada, while the boreal gene* 
are mentioned which have a more or less wide distribution throughout ©" 
whole boreal zone of the Pacific mountain ranges. 
& 
Genera found only in the Nevadan Territory. 
Exclusively Nevadan?). vl 
Libocedrus. Iris. Lewisia. 
Danthonia. Corallorhiza. Cycladenia. Fr 
Hemicarpha. Castanopsis. Boschniakta. e 
Veratrum. Spraguea. Heuchera. 
ı) The elevations above are not absolute, but vary with the slope and exposuf£. gare 
2) Genera abundant and widely distributed in spread letters: those local and % 
italics. 
