210 



150TANY 



I'AUT 1 



Sometimes they are secreted by specially constructed hairs, and in 



i. I'.'S. llnonllii iniiiiititillni'iK tram w Xnilunil, showing the cushion-like shapi- 

 of the individual plant. (From SCHIMI'KK'.S l'l<>, .'-',' ,,,/, .^ 



Datura the water is excreted 

 through the walls of the ordinary 

 epidermal cells. 



It is possible to cause similar 

 exudation of water in drops by 

 forcibly injecting water into a cut 

 shoot. 



Such exudations of water are particu- 

 larly apparent on many Aroids, and drops 

 of water may often be seen to fall within 

 short intervals, from the tips of the large 

 leaves. From the leaves of Colocasia 

 nymjilniffolia the exuded drops of water 

 are even discharged a short distance, and 

 190 drops may fall in a minute from 

 (i single leaf, while ,V litre may be 

 secreted in the course of a night. In 

 Spathodea, a tropical member of the 

 Bignoniaceae, and some other plants, the 

 space enclosed by the calyx, in which the 

 young floral organs are developed, is filled 

 with water. Again, in unicellular plants, 

 especially some Moulds, the copious ex- 

 udation of water is very evident. The 

 water in this case is pressed directly 

 through the cell walls, and in some cases 

 also, as is the case in water plants, through 

 the easily permeable cuticle ( 31 ). 



Fin. i-."4. A< ..... la MarptMota, :m Australian The organs for the discharge 



-.rl.'mpiiyllotis plant, showing pl.yllodfs. o f water, which HABERLANDT has 



collectively termed . hydathodes 



(p. 108), in some instances, actively press out the water; or, on the 

 other hand, they may simply allow it to filter through them when 



