1910] Evans, — Notes on New England Hepaticae,— VIII — 195 
face and the triangular faces a narrow pale brown wing is developed, 
the margin of which is minutely and irregularly crenulate. 
As shown by the synonymy A. sorocarpa is one of the component 
parts of R. minima L. The Linnaean species was based on three 
non-binomial species published prior to 1753. The first of these was 
Riccia frondibus glabris bipartitis acutis L. (Fl. Suec. 341. 1745); 
the second, Riccia minima, nitida, segmentis angustioribus, acutis 
Mich. (Nov. Plant. Gen. 107. pl. 57, f. 6. 1729); the third, Lichen 
omnium minimus, foliolis scissis, super terram expansis Dill. (Hist. 
Muse. 534. pl. 78, f. 11. 1741). If reference is made to the Flora 
Suecica it will be found that Linnaeus first described his non-binomial 
species in 1741 (Kongl. Svenska Vetensk. Acad. Handl. Stockholm 2: 
209), the same year in which Dillenius published his Historia Musco- 
rum. In both places Linnaeus quotes Micheli's plant as a synonym, 
while the Dillenian species, as would naturally be expected, first 
appears as a synonym in the Flora Suecica. In the absence of a 
Linnaean type for R. minima, it becomes necessary to interpret the 
species from the descriptions, figures, and specimens of Micheli and 
Dillenius. Levier! has clearly shown that Micheli's species is what 
is now known as R. nigrella DC., while Lindberg? has proved the 
identity of the Dillenian species with R. sorocarpa Bisch. The 
question at once arises, for which of these two distinct species should 
the name A. minima be retained? "The application of either the 
Vienna Rules for Nomenclature or the American Code would indicate 
R. nigrella, in spite of the fact that Lindberg and Arnell,? Schiffner,* 
and Howe? have decided in favor of R. sorocarpa. Possibly their 
decision was based on the fact that the only stations mentioned by 
Linnaeus under his non-binomial species are in Sweden, where R. 
nigrella has not yet been discovered. It should be remembered, 
however, that the two early works in which the species is referred to 
were devoted to the flora of Sweden, and that Linnaeus certainly 
implied a much more extensive distribution for his plant by quoting 
the species of Micheli and Dillenius. In the Species Plantarum he 
describes the habitat as * Europe," without citing definite localities. 
Levier, who has treated the question at considerable length, wisely 
1 Rev. Bryol. 20: 101-105. 1893. 
? Acta Soc. Sci. Fenn. 10: 471. 1875. 
3 Kongl. Svenska Vetensk.-Akad. Handl. 235: 14. 1889. 
4 Engler & Prantl, Nat. Pflanzenfam. 13: 15. 1893. 
5 Mem. Torrey Club 7: 23. 1898. 
