188 THE ZOOLOGIST. 



concern us, since their leaves are not so constructed as to form 

 permanent water-reservoirs. 



The Bromeliacece are confined to the tropics of the New 

 World, and to understand their importance as reservoir-plants, 

 one must realize the immense numbers of individual bromelias 

 of the epiphytic kinds which are present throughout great forest 

 areas in Central and South America and the West Indies. 

 They are one of the most striking features of neo-tropical 

 vegetation, and in many places are so numerous that they seem 

 to push and crowd one another to obtain a foothold on branches 

 of trees. Figure 1 shows a large number of a species of 

 Tillandsia growing on quite a small tree ; in figure 2, large 

 specimens of more than one epiphytic kind are seen held up to 

 view. For these two figures and the diagram (figure 3) I am 

 indebted to the courtesy of Monsieur Picado, in whose paper 

 they were published ; as I possess no photographs of bromelias 

 he has allowed me to republish these. In many places where 

 these plants abound, there is no other permanent water save 

 that which collects in them ; I have myself seen a big area of 

 forest covering a mountain-top in Trinidad, and other pieces of 

 forest in Dominica, where this was so.* The bromelias and their 

 contained water and detritus may be regarded, as Monsieur 

 Picado has most aptly expressed it, as a great permanent marsh, 

 broken up into countless small parts, which are elevated at 

 various heights above the ground. 



Environmental conditions of the "bromelia-marsh" and their 

 effect on the fauna. — The bromelia-marsh has several other 

 peculiarities as a habitat for marsh-living animals. First, in 

 many places the water never dries up. Though it may evaporate 

 considerably during the hot hours, it is daily replenished by the 

 condensation of atmospheric vapour in the form of mists, as well 

 as being frequently reinforced by rain. Secondly, the water is 

 not foul. Though containing animal and vegetable debris, it is 

 free from accumulation of decomposition-products. This most 

 important fact is due to the action of the plants themselves. 

 The roots of epiphytic bromelias usually act only as holdfasts, 

 fastening the plant firmly to the branch on which it grows, but 

 taking no part in its nutrition. The plant lives entirely on the 

 :: Ann. Mag. Nat. Hist., sen 8, vol. x., 1912, p. 424. 



