EPIPHYTES AND PARASITES 



remain in solution, and that the water shall not evaporate, the 

 plants bring the tips of their leaves together, thus covering the 

 reservoir. 



In most of the epiphytes the roots and the leaf-insertions, which 

 are pressed tightly against the bough, form ledges on which dust 

 and fallen leaves are collected, whether these leaves come from the 

 plant itself or are blown or fall thither from other plants. To these 

 are added scraps of bark and other debris from the tree on which 

 the plant is growing, and the whole yields a kind 

 of humus. Certain epiphytic ferns provide them- 

 selves in this way with a sort of flower-pot full of 

 humus, into which they plunge their roots, send- 

 ing these not downwards, but sideways, and even 

 upwards. For in many ferns the cavity in the 

 centre of the rosette of fronds serves to collect dust. 

 Other ferns, however, apply their fronds to the 

 trunk of the tree in such a way that the lower ^-^ 

 edges and sides touch the bark, leaving an open- 

 ing above. The rain carries dust and dirt into the 

 receptacle thus formed, which again constitutes a 

 sort of flower-pot. With the help of such little 

 collections of humus these ferns grow to such a 

 size that a single plant may weigh a hundred- 

 weight. In Ceylon I often admired the Bird's-nest Fig. 7.— The "Grey- 

 fern, whose narrow fronds form a dense bush, and beard," an epi- 

 the Antler fern, whose fronds, waving high over- 

 head, have the form of an elk's antlers. 



In the brightly-lighted woods of Pernambuco 

 one often sees objects like long white feather 

 boas hanging from the boughs; sometimes as 

 many as ten or twenty in close proximity, 

 one of these white objects we find that it consists of long, 

 fine threads; the BraziHans aptly call it "Greybeard," Barba da 

 velko (Fig. 7) ; and when a number of these white veils are seen 

 fluttering from the trees the wood really has a senile and moribund 

 appearance. One would hardly believe this remarkable object to be 

 a plant ; at the most, one would take it for a lichen, and the birds 

 appear to be of this opinion, for they use the white threads as 

 nesting-material. But the threads continue to grow, and the nest 

 becomes a living fabric. The "Greybeard" has renounced many of 

 the ordinary features of a plant. It has lost its roots ; we see nothing 



109 



phytic Bromelia. 

 On the right, a 

 plant in flower, 

 enlarged. {From 

 nature, and after 

 Warburg) 



If we examine 



