LIFE HISTORY OF A LIVERWORT 221 
they twist with a jerking motion, which helps to project 
the spores out to a distance from the parent plant. The 
advantage of this is self-evident. 
201. Germination. In some, if not all, species of 
Anthoceros, the spores germinate best after a resting 
period of several weeks or months. Early in germination 
chlorophyll develops in a plastid contained in the spore, 
and a germination-tube, or protonema, forms, long in 
some species, shorter in others, and at the tip of this tube 
a thallus develops. 
202. Summary of Life History. The life history of 
Anthoceros is, in outline, as follows (it is illustrated dia- 
grammatically in Fig. 167): 
OUTLINE OF LIFE HISTORY OF ANTHOCEROS 
Anthoceros-plant (gametophyte) 
Ar 
~~ 
Mature sporophyte (mature zygote) 
_ ^ } Reliction 
Spore Spore Spore Spore 

Protonema 
* 
Anthoceros-plant (gametophyte) 
