186 



A TEXTBOOK OF BOTANY [Cn. IV, 10 



the supporting plant is precarious, and they remain compact 

 with very short stems often concealed completely by crowded 

 leaves. Their water supply comes from the rain which wets 

 the bark on which their roots grow ; but a few possess methods 

 of collecting the rain in funnel-shaped cups formed by their 



leaves (Fig. 127). All 

 epiphytes, indeed, show 

 marked water-conserving 

 features, including thick- 

 ened epidermis, sunken 

 stomata, storage tissues, 

 and other features associ- 

 ated with plants which 

 must stand frequent dry- 

 ness (page 69). Their 

 supply of mineral matters 

 is such only as they can 

 derive from the decaying 

 vegetation amongst which 

 they live, and much of it 

 comes from the bark into 

 which they send their 

 roots. Some kinds, how- 

 ever, collect among their 

 leaves the bark, twigs, 

 flowers, etc., which fall 



FIG. 128. An epiphytic Fern, Platy- f ' ii jr 



cerium grande, possessing two kinds of rom abOVC, while others 



fronds, ordinary (drooping) and humus- possess leaves SO adjusted 

 collecting (upright) ; XT. (From Goebel.) ,. 



to the supporting trunks 



as to form half cups in which bark and other materials 

 streaming down with the rain are caught and held, later 

 decaying to a humus from which both water and mineral 

 matters are readily absorbed (Fig. 128). And many other 

 interesting features, some structural and some self-adjustive, 

 are known to accompany the epiphytic habit. From the 

 penetration of dead bark for rain water to a penetration of 



