Chap. IV] TROPICAL DISTRICTS CONSTANTLY MOIST 301 



other countries. Yet it does not contain, as for instance do the forests of Brazil, 

 Guiana, and the West Indies, large and small forms of plants crowded together in 

 rich confusion, so as to utilize the available space to the utmost conceivable degree ; 

 in it there is rather a rich repetition of certain forms developed into giants which 

 invest it with an imposing uniformity. 



' It admits the visitor, as it were, into a vast, green, vaulted hall. The roof of 

 foliage is raised aloft twenty meters above the ground by countless columns, often 

 marvellous in shape. Huge stems, without a branch, straight as an arrow and 

 cylindrical, and mingled with them weaker ones that are gnarled, bent, and re- 

 peated^' branched, all lose themselves overhead in the loose mass of leaves, which 

 is traversed at many places by richly foliaged lianes. A subdued, mysterious light 

 enfolds the bright-barked, silvery-grey or brownish boles, whilst here and there, as 

 in a church, the sun's rays play in quivering golden beams. Evergreen trees as tall 

 as our finest German trees constitute the chief mass of the forest, with their tops 

 closely interlaced. Above this dense leaf-canopy that is interwoven with climbing 

 plants, mighty deciduous trees, resembling our beech-tree, project and do not display 

 their finely branched crowns before a height of thirty to fifty meters. Most of the 

 trunks exhibit in most striking manner a tendency to produce buttresses at their 

 base V 



After a detailed account of the buttresses and of the lianes, the author continues : 

 ' Epiphytes never become attached to the bright smooth stems ; even mosses are 

 relatively uncommon. The underwood is scantily represented, only dense collections 

 of one leafy plant with straight, very long, climbing stems occupy certain tracts. 

 A layer of dry foliage covers the ground and, embedded in it, fallen pieces of wood 

 lie mouldering. Wherever one of the towering giant-stems, in a crashing fall, has 

 crushed all the forest-growth beneath, daylight streams through the wide gap in the 

 leaf-canopy and humbler forms of plants have established themselves, whilst young 

 trees struggle upwards in keen rivalry. . . . Even though the mass of foliage, formed 

 of layers piled one above the other, appears to constitute a completely closed cover 

 to all that stands beneath, yet its texture is loose ; the leaves for the most part are 

 arranged in tufts at the end of the twigs, and the latter are not so much subdivided as 

 in our German forest-trees. Hence, everywhere, rays of light can pass through the 

 leaf-canopy, and, even though repeatedly interrupted, eventually reach the ground.' 



The East African rain-forest is more poorly developed than is the West 

 African, both in expanse and luxuriance of vegetation ; it appears to be 

 chiefly confined to the mountain gorges. The flora of the rain-forest of 

 Usambara has been studied by Engler : — 



Among its already known trees, the following among others are remarkable for 

 their height or other qualities :— Mesogyne insignis ; Paxiodendron usambarense 

 (Lauraceae) ; Albizzia fastigiata ; Sorindeia usambarensis (Anacardiaceae) ; Stearo- 

 dendron Stuhlmannii (Guttiferae) ; Chrysophyllum Msolo (Sapotaceae). These 

 trees are 30 to 60 meters high. Smaller trees are, for example, Ficus Volkensii 

 (15 meters); Myrianthus arborea (10 meters, Urticaceae) ; Dasylepis integra (up to 

 10 meters, Bixaceae) ; Oxyanthus speciosus (up to 10 meters, Rubiaceae). As 



1 Pechuel-Losche, op. cit., pp. 142, 145. 



