ABSORPTION-CELLS ON LEAVES. 239 
this is the case, teeth of the kind are found on this narrow green ridge which runs 
along the groove. In Telekia, a handsome herbaceous plant of wide distribution in 
the south-east of Europe, these teeth—conical or club-shaped—springing from the 
margin of the petiole-groove are incurved, and are in general so placed that their 
blunt apices prceject into the groove. But precisely on these obtuse tips of the 
teeth are situated cells with very thin outer walls easily permeable to water, and 
having contents with a strong attraction for it. Thus, as soon as the groove of the 
Fig. 56.—Water-receptacles. 
1In a Teasel, Dipsacus laciniatus. 2 In the American Silphium perfoliatum. 
petiole is filled with rain, collected from the surface of the leaf, the tips of the 
conical teeth are moistened, and they suck up the water. 
Lastly, we have to mention the curious receptacles appertaining to foliage- 
leaves in which water from the atmosphere accumulates and continues to stand for 
weeks without being protected from evaporation by the excretion of special 
substances. Any region or portion of the leaf may participate in their construction. 
In Sazifraga peltata the lamina is shaped like a shield and forms a shallow plate 
with the concave surface turned to the sky. In the Cloud-berry (Rubus Chame- 
morus) the formation of basins is brought about by the margins of the reniform 
lamina being superimposed over one another as if to make a spathe. In the various 
species of Winter-green, especially in Pyrola wnijlora, the pale cauline leaves, 
