u8 PLANT GEOGRAPHY 



in a wild state. In the north-west, however, where 

 grasses do not flourish, the deeper-rooted bushy plants 

 predominate. This thorn-savannah is known as the 

 " Chanar " or " Espinal " region from Gourliea decorti- 

 cans Gill., the " Chanar," a leguminous shrub, and an 

 Acacia (Prosopis alba Gris.) known as " Espinillo." 

 Aspidosperma Quebracho Schlecht. and species of Cactus 

 are also characteristic. Further south, at the foot of 

 the Andes, are "Las Salinas" of the Argentine, where 

 vegetation is practically confined to a few woody and 

 succulent Salsolacece. East of this lies the true pampas, 

 a typical grassland, like the prairies of the west-central 

 United States. A moderate rainfall, well distributed 

 throughout the year and sufficient to keep the air moist 

 during the vegetative period, though unsuited for trees is 

 ideal for grass. The introduced Milk Thistle (Silybum 

 Marianum Gart.) and Cardoon (Cynara Cardunculus L.) 

 have, however, ousted the Grasses over many square 

 miles of area, forming impenetrable thickets. 



About the parallel of 40 S., at the northern boundary 

 of Patagonia, where the almost constant wind is from 

 the north-west, i.e. is desiccated by the Andes, the 

 grassland ceases, Grasses are represented by stiff dry 

 species of Stipa and Melica, and the thorny shrubs of 

 the north-west extend to the east coast. 



On the other side of the Andes the Antarctic Forest 

 Region, with a rainfall distributed throughout the year, 

 brought by the north-west winds, and a milder climate 

 than that of Northern Europe or the Alps, has many 

 evergreen trees, although growth ceases in winter. In 

 the north, including the island of Chiloe, the forests 

 contain Lauracece, Myrtacece, and Oleacece, and even 

 Bamboos and lianes, though not in the same abundance 

 as in the tropics. In the south, in the tropophilous 

 Beech forests of Fuegia, the evergreen Fagus betuloides 

 Mirb. is succeeded by the " summer green " F. antarc- 

 tica Forst. (the parasitic Myzodendron growing on both), 

 and accompanied by Drimys Winteri Forst., Berberis 

 ilicifolia Forst., and the ericaceous Pernettya, while the 

 ground is carpeted with Liverworts, Mosses, and such 

 Ferns as Gleichenia acutifolia and Hymenophyllum pec- 

 tinatum Cav. 



The presence at heights of 1 800-3000 feet in Tierra del 

 Fuego, 6500 feet in Valdivia, and 10,000 feet on 



