APPENDIX 



giant forest tree. The Freycinetias, combined with big Aracece, twist 

 around the trees, and help with their tufts of long leaves to give that 

 exotic aspect which is so fascinating in the equatorial forests. 



Epiphytes. — To endeavour to treat, even in the most general manner, 

 of the Bornean epiphytes would require a volume, so numerous are the 

 adaptations and special modifications which these plants have assumed 

 to succeed in surmounting the enormous difficulties besetting the mode 

 of life they have chosen, and to find the means of maintaining themselves 

 in situations where water and nutritive matter is either wanting or de- 

 ficient. But the necessity of avoiding the competition of other plants 

 has enabled them to get the better of these difficulties, and to establish 

 themselves on different ground from that occupied by more powerful 

 competitors. 



For many plants the thirst for light may be supposed to be the cause 

 which has determined their migration from the ground ; but the epi- 

 phytes which love shade and live on the lower and bare portion of the 

 tree-trunks are numerous. A great many orchids, screw-pines, and 

 Freycinetias, as well as aroids, ferns, etc., show the same tendency. 

 Those epiphytes which live on the elevated parts of trees derive their 

 nourishment from the air and rain, but probabty in a greater measure 

 still from the maceration and moisture of the bark of the tree to which 

 they adhere. Such epiphytes very frequently take root on their host 

 among mosses and minute ferns, not requiring much more than the point 

 of attachment and profiting by the small amount of humus which slowly 

 forms there, often augmented by ants, who take advantage of the shelter 

 afforded by the roots of epiphytes to accumulate round them heterogen- 

 eous particles primarily for their own use, but ministering at the same 

 time. to the requirements of the plants under which they have sought 

 cover. 



No one will deny that epiphytes must have derived their origin 

 from terrestrial plants. When the forest rendered the development 

 of certain plants impossible, by reason of the shade which stunted their 

 growth, and perhaps the dampness of the soil, or else on account of that 

 tendency, so common amongst living beings, to strive to get above each 

 other, a given number found their salvation at higher altitudes where, 

 though they were able to satisfy their craving for light, they were never- 

 theless compelled to struggle against hunger and thirst. 



The deficiency of water which all epiphytal plants must have ex- 

 perienced in passing from a terrestrial to an arboreal existence has been 

 the origin of a multitude of adaptations for procuring it, or for storing 

 up what came to them in the shape of rain or aqueous vapour. Indeed 

 one of the principal conditions of existence in epiphytal plants is the 

 economy of water, which they attain in many and- various ways, but. 

 especially by preventing, or at least rendering difficult, all evaporation 

 from their tissues by the thickening now of one, now of another organ, 

 in which they accumulate the necessary amount of fluid ; or, on the other 

 hand, by means of special adaptations for facilitating the absorption of 

 aqueous vapour. 



Amongst the Bornean epiphytes are to' be found all the most varied 

 forms of adaptation which this group of plants can show within the 



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