acne ae 
414 The Botanical Gazette. 
phantorhiza Burchellii, which has a huge watery rhizome, — 
sometimes weighing ten pounds. Several Asclepiadez of the 
Kalahari region accumulate so much water in their tubers that 
the bushmen often depend entirely on it. The Stapelias and 
Euphorbias store the water in their stems and retain it with 
great tenacity. The remarkable Cissus Cramerianus of Da- 
maraland has a large fleshy trunk and develops onlyafew 
thick branches. ae 
Too rapid evaporation may also be prevented by sap con- 
Marlothii. The salt is often deposited in such quantities that 
during the drying of the plant it crystallizes and forms a thick 
crust on it. he 
Hairs, glands or sheaths are the organs which enable the 
plant to absorb the dew. This is for instance the case WIM 
Salsola Zeyheri from the Kalahari region, where rain 1s rare 
The depressed glands at the base of the leaves of Acacia 
seem to serve for the same purpose, for drops of dew run ng 
down along the rhachis must moisten them. Watsomia a 
iana is protected by the large sheaths, which were found 
contain water even many weeks after rain has fallen. _ 
; THEO. Ho 
one 
