44 CHAPARRAL. 
BROADLEAFS. 
Quereus) aeritolia ss oa eee California live oak. 
Quercus Tealikormica = sae aaa a California black oak. 
QuercusxchrySolepise= =a Canyon live oak. 
Quercus densiflor; =. ene California tanbark oak. 
QOuercuss@oweslasie es ae Rock oak. 
Oiwer cused UINO Saar ee e Scrub oak. 
Quercus engelmanni_____________ Engelmann oak. 
Overcus seam Delis ene ee Gambel oak. 
Quercus? pricei[-3 i. 2a Price oak. 
Quercus lobata sso eee White oak. 
Quercussoblongifolhia= == Blue oak. 
Quercusswislizeni= see ee eee Highland oak. 
MOISTURE-LOVING BROADLEAFS. 
Acer yma crop hy lun ee Oregon maple. 
ACEr NeSUNGOn2 sae eS eee eee Boxelder. 
INUSSEhOmM pikes White alder. 
Red alder. 
California walnut. 
California sycamore. 
Fremont cottonwood. 
Black cottonwood. 

Alnus oregona_____— ls 
Juglans californica______ 
Platanus racemosa_ 
Populus fremonti_ rei ie 
Populus trichocarpa a 








Sallixeslaeyien tae _______-_Smoothleaf willow. 
Salix lasiandra sess ee Western blacks walllowar 
Salix. UVa bihiGs a2 ee ee Longleaf willow. 
Salix: dasiolepis== 2 ee Wihiteswallovs 
NSH Ip er a feat it Pa ea ese ah Ei Black willow. 
Salix scouleriana_ nae _-Nuttall’s willow. 
Salliixes SESS] iso tee meee Silverleaf willow. 
Umbellularia californica_________ California laurel. 
SUBTROPICAL. 
Neowashingtoniana filamentosa__.Washington palm. 
There are many isolated groups of spruce, pine, and oak through- 
out the chaparral region, varying in size from a group of a dozen or 
more trees to a stand covering many acres. Again, individual trees 
may be found growing far from others of their kind. Yet where 
chaparral holds complete possession of the ground it is plain that it 
does so because of the inability of the larger tree species to extend 
their range farther than they have already done. The coniferous 
forests on the higher slopes above the chaparral areas are well situ- 
ated to distribute their seeds to the lower levels, yet the limits of the 
coniferous forests remain where they have always been. Here and 
there throughout the chaparrad area exceptional conditions of soil or 
climate favor the larger tree species as against the chaparral, and it is 
on these areas that the isolated groups of spruce, pine, and oak grow. 
That favorable conditions which have resulted in the growth of 
