442 



Here belongs the case which Haberlandt' describes in a Liane, Cono- 

 cephalus. He describes the formation of compensatory hydathodes, after 

 the normal organs of the leaves have been poisoned. The extremely 

 abundant nocturnal transpiration takes place at the base of the shallow 

 depressions on the upper side of the leaf by means of sharply differentiated, 

 epithemial hydathodes with water pores always lying over the juncture of 

 vascular bundles. Where these organs had been poisoned by painting the 

 It-af with a 0.5 per cent, alcoliolic sublimate solution, small knots were 



Fig. 79. Stem of Lavetera trimestris 

 — with intumescence. (Orig.) 



Fig. SO. Brancii of Acacia pendulata- 

 with intumescence. (Orig.) 



Fig. 81. 



Magnified section of Fig. 

 (Orig.) 



formed above the vascular bundles. Each morning large drops of water 

 were found on these places. These knots, which had assumed the function 

 of the dead hydathodes, seemed to be composed of long, pouch-like cells, in 

 the lower part divided by cross walls adjoining one another (without inter- 

 cellular spaces). The club-like swollen ends separate from one another 

 like a brush. They have been produced by the elongation of the conductive 

 narenchyma cells and often of the palisade cells and have broken through 

 the epidermis. 



1 Haberlandt in 

 1899, p. 287. 



•Festchrift fiir Schwendener," cit. in Naturwiss. Wochenschr. 



