208 PLANT LIFE 
become detached as a sort of bud or gemma, 
and so reproduce the parent plant. Mosses 
and liverworts are freely reproduced in this 
manner. The gemme are of all shapes and 
sizes. They may be produced in a variety 
of ways, e. g. as biscuit-like outgrowths from 
the leaves, and sometimes, as in the moss 
Tetraphis, the whole of the leaves at the 
growing point of older stems may develop 
into reproductive bodies of this kind. Pro- 
pagative outgrowths may also occur on the 
underground parts of the stems of mosses and 
liverworts, and they are often filled with 
reserves of food. Thus they enable the 
species to tide over periods of drought, etc., 
which might easily prove fatal to the indi- 
vidual. On the return of better conditions 
they sprout, and thus reproduce the plant 
afresh. 
Passing to the higher plants, the vege- 
tative propagative processes are seen to 
exhibit almost infinite variety. The smallest 
parts of some plants are capable of reproducing 
the whole—as any one may discover who 
endeavours to eradicate troublesome weeds, 
e.g. bindweed, from a garden. The regular 
storage organs, bulbs, tubers, etc., are speci- 
ally fitted to serve as propagative organs on 
account of the stock of organic food they 
contain. Bulbs, for example, consisting of 
a short squat stem bearing fleshy leaves, 
form the ordinary propagative bodies of lilies. 
Even a single scale, detached from the bulb 
