CACTUSES IN- DOORS AND OUT. 



463 



that they are endemic, and therefore to be considered as 

 belonging to the natural vegetation of these islands. 



"In South America, north of the equator, as in Mex- 

 ico, the cactus is an indication of extreme heat and 



Fig. K. Euphorbia meloformis, 



drouth. No cactuses are found on the bay Choco, but on 

 the coast of Venezuela they are sometimes the predom- 

 inating form of vegetation. On the seashore of La 

 Guayra, they consist of branched cereuses and opun- 

 tias ; from the hot cliffs spring the melocactus, while 

 the mamillarias seek the shady places. So here the 

 cacti extend from the sea level to an elevation of 2,000 

 feet, where the forests 

 begin. 



"In no part of Bra- 

 zil are the cactuses, the 

 branched pillars of the 

 cereus and the fiat- 

 stemmed opuntia, so 

 numerous as in the pla- 

 teaus. They also flour- 

 ish well upon the light 

 soil of the open woods. 

 The Brazilian forms of 

 cacti are closely related 

 to those of Venezuela 

 and Mexico. 



"They are also very 

 abundant in the Andes, 

 being found westward 

 from the eastern ridge, 

 and are especially nu- 

 merous in the high- 

 lands of the Pacific 

 slope. They form the 

 most important con- 

 nection between the 



flora of the Mexican and Peruvian Andes. On parts of 

 the pampas the cactus forms nearly the only covering 

 of the soil. The pampas seem generally to be too moist 

 for the cactus, but on the Chamarsteppe they are found 

 both in the bush and in the forest. They also appear 



along the Parana, where the clay soil dries out. Here 

 grows one of the largest species, a pillar-cactus, attain- 

 ing a height of from 20 to 30 feet. On the steppe of 

 Cordove a large opuntia is found, having white thorns 6 

 to 9 inches in length. Twelve smaller species have been 

 distinguished near Mendoza ; among these, cereus, opun- 

 tia, mamillaria, in their different forms. As in the 

 prairies, these forms are found in the higher latitudes, 

 but their number constantly diminishes. In Patagonia 

 only the Optnitia Dar-iniiii is found, in the same manner 

 as in Missouri. In the Andes mountains, from Santiago 

 to Mendoza, there are found several species of melo- 

 cactus and opuntia, growing at an elevation of 12,000 

 feet. They are covered with a woolly material, and are 

 quite small. " 



The distribution of the cactus-form euphorbias is ep- 

 itomized as follows by the same author : 



"The fleshy euphorbias in the Old World take the 

 place of the cactuses in New World. In the Sahara 

 they are not very abundant, as their African center is in 

 the Cape region. A Nubian euphorbia, E. cundclabrum, 

 grows to a height of 30 feet, spreading its branches far 

 apart. Euphorbias are also found in the Kalahari 

 desert, which contains many of the forms found in the 

 Sahara. Upon the barren, rocky soil of the Karroo- 

 steppe, in the Cape region, all sizes of cactus-like eu- 

 phorbias may be found, while the naked forms grow 

 abundantly around Algoa Bay. 



"Only one form of euphorbia is said to appear in 



Fig. L. RHIl■^.\LI^ s.-\lii oknuides. 



Australia, where it grows on the steppes of Spencer's 

 Gulf. 



"In the Canary Islands the euphorbias are found 

 growing at a height of 1,500 feet on the north side and 

 2,500 feet on the south side of Mt. Teneriffe. The 



