1 86 NATURAL SCIENCE. Sept., 1893. 



unless we suppose that the epiphytic ancestors of the plants possessing 

 them were once much nearer the ground than their present represen- 

 tatives are. 



The plant, then, having become an Epiphyte occupying the lower 

 regions of the forest, its next demand would be to get into more 

 strongly-lighted places so as to assimilate at a greater pace. So the 

 next step was for the Epiphytes to climb higher up the trees. With 

 this arose the necessity for provision against excessive transpiration and 

 for more elaborate organs for absorbing water. Gradually, then, the 

 Epiphytes crept up the trees, becoming more adapted to their habitat 

 as they struggled with one another (and with their hosts) in the fierce 

 battle for light. In this manner they reached the higher branches of 

 the trees — but below the tree-tops. This is the paradise of the 

 Epiphytes ; the light is not too intense, but filters through a veil 

 of leaves. 



To escape their many competitors, a few bolder spirits 

 advanced almost into the full blaze of the sun on the tree-tops, 

 taking measures, as they ascended, to avoid being parched. 

 From these points of vantage, some of them, and a few from the 

 middle stratum, winged their way to the savannahs, others climbed' 

 mountains and became tropical alpine forms living on the ground (1). 

 Still others journeyed to the sea-coast, and descending to the ground 

 became littoral forms with their roots dipping into the salt-laden soil 

 (1). A few which have entirely, or almost entirely, deserted their 

 epiphytic mode of life bear structural evidence of their former 

 epiphytic mode of existence (6). 



REFERENCES. 



1. Schimper, A. F. W. — Ueber Schutzmittel des Laubes gegen Transpiration 

 besonders in der Flora Javas. Sitzungsber. d. Konigl. preuss. A had. d. 

 Wissensch. Berlin, 1890, p. 1045. 



2. . — Die epiphytische Vegetation des Amerikas. Bot. 



Mittheilungen aus den Tropcn, ii. 



3. Goebel, K. — Epiphyten. Pflanzenbiologische Schilderungen, i. 



4. Loew, E. — Anfange epiphytischer Lebensweise bei Gefasspflanzen Nord- 



" deutschlands. Verhandl. d. Bot. Ver.Prov. Brandenburg, vol. xxxiii. 



5. "Willis, J., and Burkill. — Paper in Proc. Cambridge Phil. Soc, 1893. 



6. Groom, Percy.— On the Velamen of Orchids. Annals of Botany, vol. vii. 



7. Treub, M. — Sur les urnes du Dischidia rafflesiana. Ann. Jard. Bot. Buitenzorg, 



vol. iii. 



8. Groom, Percy.— On Dischidia rafflesiana. Proc. Roy. Soc, vol. liii. 



9. Treub, M. — Sur le Myrmecodia echinata. Ann. Jard. Bot. Buitenzorg, vol. ii. 



Percy Groom. 



