LIFE HISTORY OF A LIVERWORT 
217 
to tide over periods of drought. Tubers in liverworts were 
first discovered and recognized in a species of Anthoceros. 
At least two species (Fossombronia tuberifera and An- 
thoceros tuberosus] received their specific names from their 
FIG. 162. Anthoceros phymatodes. Portion of thallus showing develop- 
ing tubers. X about 15. (After M. A. Howe.) 
characteristic of forming tubers. In some species the 
tubers appear as swellings or outgrowths on the under- 
side of the thallus; in others (Figs. 162 and 163) as en- 
largements of the tips of thallus-lobes. The leafy liver- 
wort, Bryopteris filicina (Fig. 164), illustrates vegetative 
multiplication by stolons. 
FIG. 163. Anthoceros phymatodes. Mature tuber, sprouting. X about 
21. (After M. A. Howe.) 
198. The Sporophyte. After fertilization the oosperm 
develops a young embryo, and from the lower or basal 
half the foot develops, with projections reaching down 
into the tissue of the gametophyte (Fig. 165). After the 
