The Genus Riccardia in Chile. 



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are in two layers, and their structural features can be best demon- 

 strated just before maturity. From a taxonomic standpoint the 

 character and distribution of their wall-thickenings, which are 

 nodular or in the form of half-rings, are of much interest. These 

 thickenings, in the case of the European species of Riccardia, 

 have been found to yield specific characters of much constancy. 

 They would probably yield equally constant characters in the case 

 of the Chilean species, and the lack of good capsules in the speci- 

 mens available is therefore especially to be regretted. 



