208 



DISTRIBUTION OF PLANTS. 



low depressions, the sod became wet or marshy; and in such situa- 

 tions, large-fiowered stemless Composltce were rather frequent among 

 the grasses. — 3. On mountain-peaks, high and broken, grasses became 

 scarce, and the blackened soil proved principally bare ; the vegetable 

 growth being more congested and more exclusively alpine, and occur- 

 ring in detached beds. On approaching the snow, the soil was often 

 entirely denuded, destitute of all traces of vegetable growth ; yet in 

 exposed spots, many hundreds of feet above the regular snow-limit, 

 we could sometimes on looking upwards distinguish a tinge of green. 

 Of the places we visited, the Alpamarca mountain-peak afforded the 

 greatest variety of congested alpine plants. 



I was chiefly interested in the productiveness in genera and species ; 

 far exceeding that of alpine ground outside of the Tropics. Many 

 tribes were now for the first time seen in the alpine garb : as MaJvacece, 

 Valerianacece, ParonyvlilaceK, Orcliidacem, Amaranthacece, Gemniacece, 

 AstrcKjali and Lupines among Leguminosse, and species of BaccJiai'is 

 besides other Compositce. The Ephedra and Aldea, also present, had 

 previously been observed in the alpine garb, on the Chilian Andes. 



The presence of Cactacem in alpine ground was novel ; the species 

 moreover being of large size, invested indeed with wool, but neither 

 dwarfed nor presenting the slightest tendency to the congested alpine 

 habit of growth. 



The prevailing Tribes of plants appeared to be seven ; occurring in 

 the following order of frequency : 



1. Oraminacew, or grasses. Already noticed. 



2. CompositcB. The leading characteristic feature of this alpine re- 

 gion appeared to be the abundance and variety of stemless Composit<x: 

 these commenced sparingly in the Paramera, but in the alpine region, 

 their large and often solitary flowers, blue, yellow, white, or purple, 

 were here and there conspicuous throughout the short grassy sward. 

 Beds of depressed species of Baccharis, more condensed than in the 

 Paramera, were frequent ; composed really of low shrubs, but their 

 flowers and impacted foliage nowhere exceeding the general even sur- 

 face of the vegetable growth around. There were other alpiiie Compo- 

 sitce, allied to Fuegian species, and in like manner distinguishable 

 only by the aspect of the congested mass ; the solitary flower in each 

 crown of foliage being excessively minute, almost microscopic. 



3. Gentkmacece. Next to the stemless Compositae, the most conspi- 

 cuous and ornamental plants were Gerdianas ; abnormal however, 



