170 JOIJRXA L, BOMB A Y NA TURAL HISTOR V SOCIETY, Vol. XIX. 



that very often at night or in the early morning the green parts of 

 the plant are covered with dew, whilst all the other plants in the 

 neighbourhood are quite dry. The white crust that is seen at 

 day-time on the green branches and leaves consists chiefly of 

 chloride of sodium and calcium carbonate with some other saline 

 substances. 



Berg'ia odorata shows the tendency to crowd the leaves into 

 fascicles. Jt is evident that by this means the leaves cover and 

 protect each other and are, thus, less exposed to the heating influence 

 of the sun. Sida spinosa and rhombJfolij,, var. tetusa, look quite gray 

 from very small stellate hairs. Still better protected is Abutilon 

 graveolens which, besides having long spreading hairs, is covered 

 with a sticky coat of short hairs. Of Grewia vdlosa, which is usually 

 found in the dry parts of the Presidency, the branches are grey 

 puberulous, the upper surface of the leaves rough with stellate hairs, 

 the lower velvety, the petioles villous and the stipules hairy, the 

 flower-buds, sepals, and ovary covered with pilose hairs. 



Tribnlas lerrestris and T. alatus belong both to the desert flora. 

 Besides being protected by silky villous hairs they perform some 

 special movements by which the plant-surface exposed to insolation 

 is greatly reduced. The leaves are abruptly pinnate. Now, when 

 the heat is risino- at noon or in the afternoon, the leaflets beein to 

 turn round their own axis and, at the same time, upwards round the 

 common rhachis, till they are lying in one vertical plain with their 

 upper sides touching each other. 



Zigophyllum simple. i- and Z. coccfneum diff'er from the above 

 mentioned plants by the distinct succulence of their leaves. In both 

 species they are cylindric, in Z. simplex sessile and in Z. coccineum 

 bifoliate on a stout fleshy petiole. In the centre there is a thin- walled 

 water-tissue occupying about | of the whole diameter in the former, 

 and about \ in the latter. At the same time, the stomata are de- 

 pressed. The young branches in Z. coccineum are, besides, covered 

 with a white powdery tomenium. The leaves of i^a^owm cretica are 

 thick, approaching the type of succulent plants. The outer walls 

 of the polygonal cells of the epidermis are very much thickened. 

 Lotvs garcini is a small undershrub that grows in sandy soil. Its 

 branches are covered with grey silky hairs ; the leaflets are extremely 

 small and fleshy, both sides are clothed with grey hairs, Many 



