28o EREMOPHYTES sect, xi 



over the ground forming entangled thickets. Many of them are supposed 

 by the natives to be poisonous ; in any case it is an extremely laborious 

 and painful task to extract the spines from one's skin when once they 

 have penetrated it, especially as they are often armed with recurved 

 hooks. Species of Opuntia, armed with red and yellow spines, grow 

 along the roadsides and are always broken ; but each detached fragment, 

 as it lies on the ground, strikes root and develops into a new plant. Nor 

 are there wanting species of Agave and Yucca with their tall, dried-up 

 inflorescences. Moreover, a feeble growth of deep-rooted grass maintains 

 itself for months of the rainless season. 



These succulent deserts in North America ^ also include many shrubs, 

 such as the creosote bush (Covillea tridentata), and species of Ephedra, 

 Acacia, and of Fouquieria. 



Other Shrub-steppes. 



North America. Bushland that probably should be placed here occurs 

 in the north of Mexico, in Texas, and in Arizona. The chaparral occurring 

 in these territories mainly consists of Mimoseae (including species of 

 Acacia) and many other thorny shrubs ; in Texas it is largely formed 

 by Prosopis juliflora, P. pubescens, Cercis and other Leguminosae, Prunus, 

 Juglans nana, Morus, Rutaceae (with Xanthoxylum), Simarubaceae 

 (with Castela), the zygophyllaceous Larrea mexicana, and others. Accord- 

 ing to Bray ^ two types of chaparral occur in western Texas, and owe 

 their differentiation to climatic, geologic, and physiographical differences. 

 According to the same botanist the chaparral country is drier than that 

 of grass-steppe. In chaparral many bulbous and tuberous plants occur. 

 In the shrub-steppe of southern California Parish ^ estimates that annual 

 species form 36-5 per cent, of the flora. The shrubs are leafless here 

 during summer. 



South America. Argentina is also rich in dry, mostly thorny, bushland 

 or in bush-forest. Under this heading we must include the vegetation 

 that Grisebach * terms chanar-steppe, and Hieronymus terms ' espinar- 

 forest '. In this vegetation the leaves are so small that the long, brown, 

 long-thomed branches are more obvious to the eye than the leaves. 

 The name chanar is derived from the leguminous chanar-shrub, Gourliea 

 decorticans, which predominates in company with acacias and evergreen 

 composites (including Baccharis, Tessaria, and others). 



Of similar type is Lorentz's monte-jormation,^ in which species of 

 Prosopis, Lippia, Acacia, and Cassia are intermingled with Cactaceae 

 and Atriplex shrubs. 1 



On inland Argentine dunes other types of bushland occur with species ( 

 of Baccharis, Atriplex pamparum (half a metre in height), and the 1 

 aphyllous, switch-stemmed shrub Heterothalamus spartioides and other i 

 Compositae. ; 



Patagonian bushland on gravel soil is still more meagre and open, j 

 and is mainly formed by Leguminosae, Compositae, and Solanaceae. 



Australia. Scrub occurs in central, western, and south-western parts ; 



' Bray, 1 90 1, 1906 ; Coville, 1893; MacDougal, 1903; Karsten und Stahl, 1903. I 

 ^ Bray, 1901. ' Parish, 1903. * Grisebach, 1872. " 



* ' Monte ' signifies bushland or bush-forest. 



