Review. 
265 
In some cases ( e.g ., Aneura and Cephaloziella) great importance 
is attached to the distribution of the sexual organs, the unisexual or 
bisexual nature of the plant, being the character deciding its name. 
It may seem like heresy to the systematic bryologist to question the 
importance of this character, but a specific distinction based on 
such an unsatisfactory foundation is scarcely warrantable, especially 
when other species are not treated similarly. The paroicous and 
monoicous conditions of Calypogeia Trichomanis are not considered 
specifically distinct, but a similar sexual distribution in Cephalo¬ 
ziella causes a segregation into two distinct species, other differences 
being of minor importance in the naming of a doubtful plant. The 
same uncertainty of specific distinction is shown in Aneura latifrons 
and A. incurvata ; the former is monoicous, usually broader, more 
branched and plano-convex in section, whilst the latter is dioicous 
and concavo-convex in section. The characters separating these 
two plants are very variable, dioicous plants sometimes having 
the form and section of A. latifrons , in fact, the shape of the cross- 
section of the thallus may vary in the same specimen, in which case 
the sexual distribution seems to be the only distinguishing character 
between the two species. Cephalozia Lammersiana was regarded by 
Spruce as a larger and dioicous form of C. bicuspidata, whilst 
Macvicar considers it to be only “pseudo-dioicous,” and as “a ‘small 
species’ which is probably not always separable from C. bicuspidata .” 
In the nomenclature of mosses (2) the same unsatisfactory distinction 
occurs, Bryum bimuni, being synoicous, is separated from B. pseudo- 
triquetrum which is dioicous, the autoicous B. pallescens from the 
synoicous B. affine, the distribution of the gametangia being the 
only constant separating feature. In B. capillare the synoicous 
state is simply given as a variety of the dioicous type, and B. incli- 
natum and B. provinciate may be autoicous or synoicous, sometimes 
both arrangements of the gametangia occuring on the same plant. 
There are seven species of Aneura given ; those most recently 
segregated, A. incurvata and A. major, are probably much commoner 
than indicated, especially if the simple and concavo-convex character 
of the thallus be taken as the deciding factors of the former. The 
crassior form of A. pinguis found on sand dunes seems to be as 
worthy of a varietal name as many others which have been 
accorded that doubtful dignity. 
The use of a varietal name is, as the author says, “ largely a 
matter of personal opinion,” and probably no two hepaticologists 
could be found to agree in all cases, but the values of some of the 
varieties given in the Handbook seem unequal to me. Of doubtful 
value may be mentioned such varieties as the following, Riccia 
glmica vars. major, minor, subinermis ; R. bifurca var. subinermis ; 
R. Warnstorfii var. subinermis', Scapania gracilis var. minor; 
Chandonanthus setiformis var. alpinus ; Lopliozia Floerkii var. 
Naumanniana; Alicularia scalaris var. procerior; and Cephalozia 
media var. laxa. In most cases these are growth-forms due to habitat, 
as such a good ecologist as Macvicar no doubt recognises. The 
erect, truly aquatic form of Pellia Fabbroniana is given as var. 
lorea, the similar habitat-form of Marclmntia polymorplia is var. 
aquatica, the more xerophytic and alpine form of the latter being 
distinguished as var. alpina. 
