244 



OUTLINES OF PLANT LIFE. 



(5) In non-succulenls, the epidermis itself may be greatly 

 developed as a water-storing tissue, or it may form great num- 

 bers of bladdery hairs which 

 are richly supplied with 

 water, as in the well-known 

 "ice-plant," on which the 

 hairs glisten like ice. 



In the first case, the epi- 

 dermis, instead of forming a 

 single layer of cells, may 

 develop into several layers, 

 the lower ones large and 

 thin-walled, as in begonias, 

 figs, and peppers (fig. 208). 

 The cells immediately under 

 the epidermis sometimes 

 become transformed into a 

 water-storing tissue, as in 

 the oleanders (fig. 206) ; or 

 strips of tissue extending 

 from the upper to the lower 

 side of the leaf may act as 

 reservoirs of water. 



343. 3. Tubers and bulbs. 

 • — These forms of the shoot, 



Fig. 208.— Strip from a vertical section of , . , . , , ,. , 



leaf of Pepcromia trichocarpa. A, from Whlch are riChly Supplied 

 a fresh leaf; w, water-storing tissne, com- 

 posed of the multiple epidermis of the upper With water, may also be 

 side ; a, chlorophyll-bearing cells ; j, spongy 



parenchyma with sparse chloroplasts and COUnted, in part at leaSt, aS 

 much water. B, the same after four days' 



transpiration at 18-20° C. The tissue 111 is an adaptation for Water- 

 much collapsed, the walls being plaited; 

 s also shrunken, but a as before. Magnified Storage, 

 about 50 diam.— After Haberlandt. „ ., „ , 



344. III. Halopbytes. — 



The salt-loving plants, though they may grow where water 

 is abundant, are strikingly similar in most of their characters 

 to the xerophytes. This similarity is to be explained prob- 



