ii8 Plants and their Ways in South Africa 



plant structures and how they have come to vary. If plants 

 become fitted to their surroundings they thrive and multiply, 



FIG. 106. One of the plants described by Dr. Marloth as " PJlanzen mil 

 Fenster-Bldttern" (Plants with window leaves). A. Bulbin* mesembrianthe- 

 moides, Haw., showing ground line. The tips of the leaf wither. The light 

 passes through the transparent flat surfaces above ground and is diffused to the 

 chlorophyll situated below in a narrow marginal row of cells. The central 

 cells are water storing. B. Mesemlrianthemvm truncatum, Th. (collected by 

 Miss Taylor near Kimberley ), a, opposite truncate leaves ; b, withered remains of 

 last year's leaves ; c, capsule of last year's fruit. The leaves beneath the ground 

 line d are green ; the portion of the leaves above the soil form a red sap in the 

 cells which protects the chlorophyll below. 



if not they die out, and so the study is also connected with 

 that of geographical distribution and with the origin of plant 

 associations. 



