30 PATAGONIAN EXPEDITIONS I BOTANY. 



2. THE MOUNTAIN FLORA OF THE UPPER AYSEN VALLEY. 



A brief account of the vegetation of the mountains surrounding the 

 rather wide upper valley of the Aysen should not be omitted in this con- 

 nection, although my knowledge of it is not very comprehensive, being 

 founded only on my observations during a single ascent to the higher and 

 bare parts of one of these mountains. 



Their flora is rather diversified and their sides up to an altitude of 700 

 meters are covered with extremely dense thickets and park-like forest. 

 Above the yoo-meter-line the vegetation becomes more like that of the 

 steppe, having much in common with the flora of the treeless areas in the 

 valley and interspersed with small groves of Nothofagus pwnilio up to an 

 elevation of 1000 meters. This tree extends upward to an altitude of 

 1300 meters, continually decreasing in size, and becoming a mere bush 

 and growing in low thickets near the upper limit of its range. It is 

 accompanied by a vegetation which is very much poorer in species than 

 that of the lower and steppe-like slopes, and differently composed. Above 

 the i3OO-meter-line the vegetation is extremely thin, with very few species, 

 and at 1400 meters every trace of plant-life disappears. 



The excessively dense and almost impassable thickets of the lower 

 slopes are made up of the following species : Berberis microphylla and B. 

 darwinii, Ribes sp. (presumably R. magellanicum and R. cucullatwri}, 

 Discaria discolor, Pernettya mucronata, Colletia spinosa, Rhacoma dis- 

 ticha, Escallonia rubra, with a sprinkling of herbaceous plants, such as 

 Viola maculata, Vicia daropskyana, Elymtts alboivianus, Deschampsia 

 flexuosa and Mutisia retttsa, the last named of which is often plentiful, 

 the others being very scarce. 



Here and there small beech groves are interposed between the thickets. 

 At a height of from 500 to 600 meters I met with one grove that quite 

 unexpectedly turned out to be composed of Nothofagiis betuloides, which 

 species I could hardly have believed to exist in these dry areas. The 

 undergrowth of the grove was made up exclusively of Rhacoma disticha. 



During my ascent the last park-like forest was found at an altitude o f 

 700 meters. It was as vigorous as the forests of the valley and fully typical, 

 although Nothofagiis pumilio preponderated. The undergrowth was the 

 same as in the valley and, in addition, the following three species were 

 found : Embothrium coccineum, Rhacoma disticha and Cystopteris fragilis. 



