78 Rhodora (Max 
Y deverum, 9 flaccidum, and s pygmaeum, but acknowledging 
their unstable character. Under the first of these he recognized 
subdivisions of a lower rank (forms and sub-forms), giving them the 
names X 1 commune, X 1%. fuscum and « 2 elongatum; under the 
second he recognized the subdivisions Q 1 laxius, Q 2 innovans, 
6 2* julaceum and B 3 gemmiparum; but under the others, y, 3 
and e, he distinguished no lower subdivisions. As synonyms of 
certain of these subdivisions he cited the following species, which 
had been either published by earlier writers or distributed in exsie- 
catae under manuscript names. Jungermannia tricrenata Wahlenb. 
(1814), under a 1; J. triangularis Schleich. (1805), nomen nudum, 
under x 1 and a 1*; J. deflera Mart. (1817), under « 1*; Pleuro- 
schisma flaccidum Dumort. (1831), under Q 1; P. parvulum Dumort. 
(1831), under @ 2; and Jungermannia flaccida Schleich. (1821), 
nomen nudum, under 8. He chose the name deflexum for the species, 
rather than tricrenatum, on account of an inaccuracy in the original 
description of Jungermannia tricrenata; but of course this would not 
now be considered a sufficient reason for invalidating Wahlenberg's 
species. 
Nees von Esenbeck’s subdivisions were taken over bodily in the 
Synopsis Hepaticarum (1845), where the species appears under the 
name Mastigobryum deflexum Nees. They were adopted also by 
Lindenberg and Gottsche in their monograph of Mastigobryum,! 
published a few years later, the subdivisions « 1, æ 2, @ 1, Q 2*, 
Y, 6 and e being separately illustrated on their plate. The more 
typical condition of the species, as described above, is clearly shown 
by f. 1-4, which illustrate € 1 tricrenatum commune. Subsequent 
writers have either ignored Nees von Esenbeck's subdivisions al- 
together or have used his names very sparingly. 
For many years the species continued to be known by the name 
Mastigobryum deflecum, but this name has gradually been super- 
seded by other names. By those who recognize the genera of S. F. 
Gray the name Bazzania tricrenata is usually employed. In 1875, 
however, Lindberg? revived for the species the old specific name 
triangularis of Schleicher, forming the combination B. triangularis 
(Schleich) Lindb. He apparently dated the name from the year 
1805, when Schleicher distributed specimens of Jungermannia 
1 Spec. Hepat. Mastigobryum 108. pl. 18. 1851. 
2 Acta Soc. Sci. Fenn, 10: 499, 1875. 
