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386 ZONES AND REGIONS [Pt. Ill, Sfxt. I 



vi. FUMAROLES IN JAVA. 



Zollinger^ was the first, and he was followed by Junghuhn -, to observe 

 in Java the peculiar phenomenon that vegetation close to fumaroles is 

 chiefly composed of alpine species, even when the station is 1,000-1,500 

 meters below alpine regions. Besides the purely alpine species, there 

 appear in the vegetation around the fumaroles in Java plants which grow 

 in neighbouring forests as epiphytes, but are unknown as terrestrial plants 

 away from the fumaroles. 



The fumaroles of Java that I studied consist sometimes of drj- crevices 

 encrusted with crystalline sulphur, at other times of crateriform pools, the 

 hot water of which is frequently almost at boiling-point (according to 

 Junghuhn up to 197° F. = 92° C). and is kept violently bubbling by the 

 gases. Where these pools are collected, usually in large numbers and 

 of different sizes, the soil is a wet white claj-, which is said b}- Junghuhn 

 to arise by the action of sulphuric acid on trachyte ; it is usually covered 

 by a yellow efflorescence of sulphur. The ground is frequently so hot 

 that to remain standing on it is impossible. From all the crevices and 

 pools there escape hot vapours of suffocating odour, sometimes of K 

 sulphuretted hydrogen, at other times of sulphurous acid. The water has ^Mt 

 an acid taste and sets the teeth on edge. 



Amid these peculiar conditions, frequently close to the bubbling pools, W- 

 rooted in the hot acid soil, their foliage bathed in hot sulphury vapours, 

 luxuriant bushes flourish, and show no other effects of their environment 

 beyond, in places specially rich in vapour, a white mealy coating on th 

 cortex and leaves. 



The bushes of the solfataras are much lower in stature than the 

 surrounding forest and quite sharply marked off from it. None of the 

 small trees and shrubs that form the underwood in the high-forest appeal 

 among them ; of forest herbs only a few species represented by detached brt 

 individuals occur ; plants that occur elsewhere in the open situations 

 of the same region are entirely absent. In spite of the humidity of the 

 atmosphere and of the soil the flora of the solfataras is composed oj 

 xeroplnloiis species ; in fact, nearh' all the xerophytes of the neighbourhooc 

 are collected there. There are always numerous plants of \"acciniun: 

 varingiaefolium, which otherwise inhabits onh' the dry alpine region above 

 a,6co meters, together with Rhododendron javanicum, which thrives on the 

 topmost branches of the neighbouring forest, and Ficus diversifolia, tha 

 otherwise occurs only as an epiphyte, and, on tKe sea-shore near Singapore 

 as a halophytc. In solfataras of lower regions some other species, else 

 where epiphytic, may be added, such as Medinilla javanensis and RhodO' 

 dendron tubiflorum, whilst as the altitude above sea- level increases, th 



' Zollinger, op. cit., p. 43. - Junghuhn, op. cit., p. 453 ; also Schimper, I. 



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