Plant Communities of the World 273 



stiffened, and leathery, usually reduced in size, often hair-clad. 

 They avoid hot sun radiation by standing obliquely to the light 

 or presenting only their edges directly, as in Eucalyptus. Duri- 

 silvae thrive in the typical Mediterranean climate. A moist, mild, 

 oceanic winter is there combined with a dry, hot, continental 

 summer, and spring and fall rains occur, and winter rains in 

 the southern parts. On the whole it is not a good tree climate; 

 scrub has a greater importance in it than in other climates. 

 Durisilvae occur in California, in the Mediterranean, in Aus- 

 tralia. Around the Mediterranean are the forests of stone oak, 

 Quercus ilex, and cork oak, Quercus suber, the olive groves, the 

 date palm, the Casuarina forest; in Australia, the Jarra forest with 

 dominating Eucalyptus marginata, the Karri with Eucalyptus 

 diversicolor, the Wandoo with Eucalyptus redunca, and others. 

 In California, Cooper worked out four associations of relative 

 constancy and wide distribution. The moistest areas of Duri- 

 silvae are occupied by the tan-bark oak forest, the Pasania densi- 

 fiora — Quercus chrysolepis — Arbutus menziesii association, and 

 Pasanietum densiflorae, characteristic of the lower altitudes of 

 the northern Coast Ranges. The Quercus agri folia — Arbutus 

 association is characteristic of the outer central Coast Ranges 

 from Mendocino to Los Angeles County, and is particularly 

 well developed in the San Francisco Bay region and southward 

 to the Santa Monica Mountains. The Quercus agri folia — lobata 

 association occurs in the broad valleys and gende foothill slopes 

 of the central Coast Ranges. Higher altitudes are occupied by 

 the Quercus chrysolepis — \elloggii association, which belongs to 

 the higher Coast Ranges and southern California mountains 

 and to the middle altitudes of the Sierra. I was shown a beauti- 

 ful association of light sclerophyllous forest with grassy under- 

 growth when MacDougal took me up into the Santa Catalina 



