2l6 
STRUCTURE AND LIFE HISTORIES 
many small pieces with a pair of scissors, each piece can 
regenerate a new plant. In many species the tips of the 
lobes of the thallus become separated from the plant 
naturally, by the dying off of portions back from the tip. 
In such cases each tip develops an entire new individual. 
A thorough study of these phenomena has led botanists 
FIG. 161. A liverwort (Lunularia). Below, portions of the thallus, 
showing the lunar-shaped cupules, with brood-buds, or gemmae. Above 
a single gemma, greatly magnified. 
to the conclusion that every cell of a liverwort is able to 
reproduce an entire plant, just as effectually as though 
it were a spore. Some species produce little multi- 
cellular bodies called gemma (Fig. 161). Other species 
produce fleshy tubers, richly stored with reserve food- 
materials, 1 and specially valuable in helping the species 
1 Analogous to tuber-formation in the potato. 
