KELATIONS OF FOLIAGE-LEAVES TO ABSORBENT ROOTS. 97 
of the stem are only erect for about three-quarters of their length; the upper- 
most third, including the apex, is bent obliquely outwards and downwards. Drops 
of rain falling on this upper third of a leaf would flow in a centrifugal direction, 
and do, as a matter of fact, drip down from the apex. Now the leaves in all 
Fig. 14.—Irrigation of Rain-water. 
1In Alfredia cernua. 2 In a Mullein (Verbascum phlomoides). 
these plants are shorter the higher their position upon the stem, so that the total 
contour of the plant may be described as a slender pyramid. In consequence of 
this, water dropping from the outward-bent and drooping apices of superior leaves 
is arrested by that part of an inferior leaf which shelves towards the stem, and is 
thereby conducted centripetally. Thus all the rain-water received by a plant 
of this kind at last reaches the immediate neighbourhood of the tap-root, and is 
Vou. I. 7 
