1923] Evans, — Notes on New England Hepaticae, — XVII 77 



Hep. Bor.-Amer. 80, distributed as Masligobryum deflexum, are like- 

 wise referable to B. tricrenata; they were collected on "rocks on the 

 higher mountains" and probably came from New Hampshire. The 

 species is known also from West Ran ton, Newfoundland, A. E. 

 Waghome 163, 164, and from Mt. Albert, Gaspe County, Quebec, J. 

 A. Allen 27, J. F. Collins 4202 (see Evans, Bryologist 19: 29. 1916), 

 but most of the other records from eastern North America were 

 based on the next species. 



The wide range of variability exhibited by B. tricrenata has long 

 been recognized. Its extreme forms are so different in appearance 

 that they would undoubtedly be considered distinct species if they 

 were not connected by imperceptible intergradations. In its more 

 typical development, as represented by the figures of Macvicar 1 and 

 Miiller, 2 the characters are distinct and striking. The plants are 

 pigmented with brown, sometimes very deeply so, and grow in com- 

 pact mats or scattered among mosses. The individual stems tend 

 to be suberect; they give off numerous flagelliform branches from the 

 axils of the underleaves and occasional lateral branches of the Frul- 

 lania type, the latter forming narrow angles with the stem. The ovate- 

 triangular and persistent leaves are approximate or imbricate and 

 are strongly convex, when seen from above; the dorsal base is rounded 

 or subauriculate; and the apex shows three sharp teeth separated 

 by narrow sinuses, the acroscopic tooth projecting slightly beyond 

 the others. The underleaves are distant to approximate and quadrate- 

 orbicular in outline; the apex is broad and truncate and shows four 

 rounded to acute teeth more or less clearly; while the slightly bulging 

 sides are entire or vaguely toothed. Diverging from this type are 

 forms in which the leaves are distant, less convex, and acute or 

 bidentate; while the underleaves may have only two or three vague 

 teeth or be almost entire. It is not unusual, in fact, for a branch of 

 a typical plant to exhibit divergent features of one sort or another. 



The most thorough attempt to define and describe the numerous 

 varieties and forms of B. tricrenata was made in 1838 by Nees von 

 Esenbeck, 3 who discussed the species under the name Her pedum 

 deflexum. He recognized five subdivisions of the first rank (or 

 varieties), giving them the names a tricrenatum, $ implexum, 



i Student's Handb. British Hepatics 317. /. 1-k- 1913. 

 1 Rabenhorst "s Kryptogamen-Flora 6*: /. 76. 79. 1914. 

 » Naturgeschichte der europ. Lebermoose 3: 57-74. 1S38. 



