382 



COMPARATIVE MORPHOLOGY OF FUNGI 



formed by the expanded base of the neck, much as in the more highly 

 compound types of other genera. 



In some species, as R. dichotoma (Fig. 255, 4), R. inclusa (Fig. 256, 3), 

 R. introversa (Fig. 255, 3) and related species, there is no indication of 



Fig. 257. — Rickia rostrata. 1. Mature individual. 2. Simple secondary appendage. 

 3. Branched secondary appendage. Rickia biseriata. 4. Mature individual. 5, 6. 

 Paired and single antheridia. 7. Apex of young individual, showing trichothallic growth. 

 Rickia Coelostomalis. 8. Tip of young individual, showing cell arrangement. 9. Perithe- 

 cium with recurved neck. 10. Appendage with umbellate terminal branchlets. 11. 

 Two normal single, secondary appendages. 12. Mature individual. {After Thaxter, 1926.) 



antheridial formation; in R. Sylvestri only one is produced while in R. 

 papuana (Fig. 255, 2) and R. coptengalis (Fig. 256, 9) they are very 

 numerous, often a hundred or more in a single individual. In other 



