—86— 



of the cross section of the thallus, is not so in reality. Familler (3, p 14) has 

 shown that typical R. pseudo-Frostii, in some of his cultures, became directly 

 transformed into R. Huebeneriana, and Nicholson (6, p. 202) has confirmed these 

 results by careful observations in the field. There is every reason to suppose 

 that R. fluitans is fully as variable as R. Huebeneriana. The so-called "broad 

 form" of Von Gaisberg and the terrestrial form obtained by Donaghy in his 

 study of the aquatic R. fluitans should therefore be subjected to a more rigid 

 scrutiny than they have yet received, in order to determine whether their dis- 

 tinctive features are constant or inconstant in character. Until this is done 

 their status must remain uncertain. Renewed search should likewise be made for 

 the aquatic form of R. fluitans in fruiting condition, in order to determine whether 

 or not the marginal lobing of the Tempelhof specimens represents a constant 

 feature and also to compare the spores with those of the terrestrial form. 

 Yale University 



Literature cited 



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1916. 



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Standortsangaben. Denkschr. Kgl. Bayer. Bot. Ges. Regensburg 13: 153-305. 1917. 



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9. Bryotheca Posnaniensis 2. 1914. 



