The Genus Riccardia in Chile. 153 



are simple. The branches which are once pinnate are perhaps the 

 most typical; they are usually 1.5-2 mm. long and 0.15-0.25 mm. 

 wide. Even the narrowest branches are 0.1-0.12 mm. wide, and 

 such branches may be primary, secondary or tertiary in rank. The 

 branches are essentially the same in structure as the main axis, but 

 some of them are even less flattened and in some cases the upper 

 surface is almost plane (Fig. 5, H). On certain branches and 

 even on the main axis a vague and interrupted row of marginal 

 cells may sometimes be distinguished. 



Only a few male branches have been observed. They bore a 

 marked resemblance to those of R. alcicornis, except that the wings 

 were slightly crenulate from projecting cells. In one case a simple 

 proliferation, 1.5 mm. long and 0.15 mm. wide, had been developed. 

 The very short female branches arise directly from the main axis 

 or from the basal portion of one of the bipinnate branches. The 

 archegonia are four or fewer and are protected, much as in R. 

 alcicornis, by irregularly divided wings, two to four cells wide, the 

 divisions being lobe-like and either blunt or sharp. Supplementary 

 outgrowths in connection with the archegonia are apparently not 

 developed. In many cases the female branch proliferates beyond 

 the cluster of archegonia, and a proliferation in extreme cases may 

 take the form of a pinnate or bipinnate branch-system. According 

 to Stephani's account the young "calyptra" is villous with long 

 hooked hairs. The writer regrets that he has been unable to 

 demonstrate calyptras in the specimens at his disposal. 



The numerous proliferations growing out beyond the female 

 inflorescences are perhaps an indication that the type material of 

 A. fuscobrunnca is abnormally developed. In some cases the 

 interpretation of these outgrowths as proliferations is clear, since 

 unfertilized archegonia can be demonstrated at the base. In 

 other cases there are apparently no archegonia at the base of a 

 "proliferation", although it still shows a cluster of lobe-like 

 structures, similar to the wings of a female branch. Of course 

 it is possible that unrecognizable vestiges of archegonia are pres- 

 ent, even here, but it seems more probable that a female branch 

 may have grown out into a sterile extension without having formed 

 any archegonia at all. 



In comparing R. fuscobrunnea with R. alcicornis certain 

 resemblances are very striking. The two species are of about the 



