1923] Evans, — Notes on New England Hepaticae, — XVII 79 



triangularis in his Plant. Crypt. Helvetiae. Since it is now admitted 1 

 that Schleicher's J. triangularis is a nomen nudum, Lindberg's 

 combination B. triangularis, of 1875, represents the first adequate 

 publication of the specific name triangularis for the plant in question 

 and should not be allowed to replace the name tricrenata, which 

 clearly dates from 1814. 



1900 Pearson 2 added to the nomenclatorial difficulties involved 

 by recognizing both B. tricrenata and B. triangularis as valid species. 

 He listed, as synonyms of the latter, Jungermannia triangularis 

 Schleich. and J. deflexa Mart. According to Nees von Esenbeck, 

 however, as already pointed out, both of these species are synonyms 

 of his Herpetium deflexum a tricrenatum, under which he naturally 

 cites, as another synonym, J. tricrenata Wahlenb. It would appear 

 therefore that J. triangularis and J. deflexa should both be cited as 

 synonyms of Bazzania tricrenata, when this is accepted as a valid 

 species, and there is nothing in Lindberg's writings to indicate that 

 he ever interpreted his B. triangularis in a different and more restricted 

 sense. Pearson's B. triangularis of 1900 thus becomes a homonym 

 of Lindberg's B. triangidaris of 1875, in case each represents a dis- 

 tinct species. 



The validity of Pearson's species, however, is not above question, 

 and it is not at all certain that it represents a definite and clearly 

 defined series of forms. According to his observations it differs from 

 B. tricrenata in the following respects: the plants are smaller; the stems 

 are more slender and usually, but not invariably, dichotomously 

 "innovantly" branched; the leaves, which soon fall away, are pro- 

 portionately shorter (except in the var. flaccida) ; the leaf cells are 

 "rounder," with large and distinct trigones; and the underleaves 

 are patulous and usually subentire. In the var. flaccida the leaves are 

 described as narrower and often entire and apiculate. Except for 

 the fact that the leaves are said to be caducous, instead of persistent, 

 these differences might well come within the range of variability of 

 such a species as B. tricrenata, and Pearson himself questions whether 

 his B. triangularis may not be either the male plant or a mere variety 

 of B. tricrenata. 



As a matter of fact the specimens cited under B. triangularis do 

 not all show the caducous habit. In the material from Tyn-y-groes 



■ See Evans, Rhodora 10: 190. 1908. 



2 Hep. British Isles 130. 132. pi. *8, 1,9. 1900. 



