RELATIONS OF FOLIAGE-LEAVES TO ABSORBENT ROOTS. 93 
inclination is downwards and outwards. On their apices great drops are gradually 
formed, which finally detach themselves and fall on to the mass of needles be- 
longing to a lower branch. Thus transmitted, the rain-water travels through 
the foliage lower and lower and at the same time further from the axis. This 
is also the case with larches. The drops of rain which fall upon the erect needles 
of the tufted “short branches” collect and gradually descend to the needles of 
the drooping “long branches” on lower boughs. Large drops are always to be 
seen on their drooping apices, whence they drip to the earth. Owing to the 
pyramidal form of larches, and to the circumstance that the long shoots on each 
branch are terminal, almost all the water which falls upon one of these trees 
reaches the long shoots hanging down from the lowest branches, which discharge 
most of all. Although larches with their tender needles do not look at all as 
though they would be any protection against rain, the ground underneath them 
keeps dry nevertheless, the principal part of the water falling upon them being 
conducted to the periphery. Indeed, the larch belongs to the number of trees 
which conduct almost all the rain that falls upon them to a certain distance from 
the axis where the absorbent roots lie, and only allow a little to trickle down 
the bark of the main trunk. 
Many shrubs and perennial herbs also transmit the water, which falls on 
their upturned laminz, to parts of the ground where their absorbent roots are 
embedded; or, rather, the roots send forth their branches bearing absorptive cells 
to the area which is kept moist by drippings from the leaves. Particularly striking 
in this respect are the species of the two genera of Aroids Colocasia and 
Caladium. A specimen of the latter is figured below (fig. 131). If one digs 
about individuals of this genus cultivated on open ground, one invariably finds 
that the tips of the lateral roots, which proceed in a horizontal direction from 
the bulbous root-stock, are buried under the point of the great leaves which slope 
obliquely outwards. We must not omit to mention, in addition, that the stalks 
of leaves which conduct the rain centrifugally are not channelled on the upper 
surface; they are round, and comparable to wires supporting at their upper extremities 
the lamin in an outward and downward direction. As instances we may quote 
the Horse-chestnut, Maple, and Lime, and many shrubby, suffruticose, and 
herbaceous plants, such as Sparmannia, Spirea, Aruncus, and Corydalis, and also 
climbing and trailing plants (e.g. Menispermum, Banisteria, Aristolochia, Hoya, 
Zanonia, and Tropwolum). Whenever a system of grooves is developed on the 
surface of an outward sloping leaf, the channels run along the veins and terminate 
at the apex of the leaf, or at the apices of the leaf’s lobes, and invariably cause 
the water to travel, not to the basal part, but to a spot on the margin whence 
it will detach itself in the form of a drop, and fall upon the leaves situated 
immediately below and at a greater distance from the axis. : 
A striking contrast to these trees and shrubs, climbing and trailing plants, 
and suffruticose and herbaceous species, with their absorptive roots lying in one 
plane, and usually spreading at but little depth, is afforded by plants which possess 
