184 



A TEXTBOOK OF BOTANY [Ch. IV, 10 



While the upright self-supporting condition is typical in 

 foliage-supporting stems, modifications thereof occur in 

 comiection with special habits. Most prominent are cloib- 

 ERS, which make use of trees, rocks, walls, and other supports 

 to Uft their fohage to the fight. Being thus supported, they 

 need no great thickness and remain slender, devoting their 



,'\|H \''N ,1; ',1 



Fig. 126. — A typiral epiphytic Orchid, showing aerial roots, and the 

 pseudobulb.s, or storage .steni.s, from which spring true leaves. (Reduced 

 from Kcrncr.) 



material to increase in length. Some simply cJnmber over 

 other plants, as in case of the Rattan Palm alreatly men- 

 tioned (page 113) or theanany great lianas of the tropics, or 

 iniie Clematis of our woods. Such plants possess hooks (Rat- 

 talW', twining petioles (Clematis, Fig. ol), or other arrange- 

 ments preventive; of sli])i)iiig from the supporting vegetation. 

 Others, forming our principal vines, cling to a support, either 

 by tendrils, as in Grape and Passion Vine (Fig. 136), or by 



