186 VEGETABLE PHYSIOLOGY 
ground, on which are only a few rudimentary leaves. At 
the base of the stem there is found a cluster of fairly stout 
root-like structures which intertwine with each other to form 
@ mass sometimes as large as a man’s fist. These are 
developed only in masses of humus, from which they absorb 
the products of decay. These plants differ thus from 
normal phanerogams by their method of absorbing food. 
Their subterranean members are not provided with the 
system of short-lived root-hairs which are so characteristic 
of the ordinary roots. They are not in need of such close 
contact with continually fresh particles of soil as are the 
latter, lying as they do embedded in a mass of humus. In 
some cases all their external cells absorb material from 
this; in others special absorptive cells are present, but 
these are not localised like the ordinary root-hairs, and they 
are not being continually renewed, but remain active for 
long periods. Frequently they are only found at the points 
where contact with the humus is effected. Many of these 
saprophytes have the cells of their cortex infested with the 
hyphe of a fungus. 
The food which is thus absorbed from the decaying 
organic matter is not necessarily in a fit condition for 
immediate assimilation by the protoplasts. It may, and 
frequently does, require alteration before being available 
for nutrition. 
The plants of the next group which we must consider 
differ from the saprophytesin an important particular. Like 
them they are provided with a chlorophyll apparatus, and 
are consequently capable of carrying on carbohydrate con- 
struction. Indeed they are generally more active.in this 
respect than the members of the last group. As in the case 
of the greater number of the latter, it is chiefly their nitro- 
genous material that they obtain nearly or quite ready for 
assimilation. They appear to need this nitrogenous food 
in the form of proteins, and they obtain it by capturing 
and killing various animal organisms whose putrefying 
hodies yield them what they want, 
