Anacrogynous Jungermanniales. 2 11 
The capsule-wall splits along more or fewer of the four dehiscence 
lines laid down previously, hence the number of valves varies from 
two to four; the valves do not cohere at the top, as a rule. 
Symphyogyna (Fig. 38) differs from Blyttia and Morckia in 
having no perianth; the calyptra, instead of being thin as in these 
genera, is massive and bears on its upper portion the unfertilised 
archegonia; the involucre consists of a single scale. In practically 
every other respect, however, Symphyogyna shows an extraordinarily 
close resemblance to Blyttia , and it is very difficult to distinguish 
between sterile plants of the two genera. Moreover, the species of 
