156 | Rhodora [SEPTEMBER 
thought that the inflorescence was variable and that both monoicous 
and dioicous plants occurred. Carrington,! for example, stated that 
the species " was not always dioicous" and described androecia in the 
form of "special branches attached to the ventral surface of fertile 
shoots." Although the occurrence of ventral male branches has 
apparently not been confirmed, Arnell? states that he has observed 
paroicous individuals in material from Norway and Lower Austria, 
and Müller admits an occasional paroicous inflorescence in the species. 
Upon studying paroicous plants from the British Isles, Schiffner 
noted that this type of inflorescence was associated with larger leaf- 
cells, larger cells in the walls of the capsule, larger spores and wider 
elaters. He therefore separated these plants from N. hyalina and 
described them as a new species under the name N. paroica Schiffn.? 
a species which British botanists have been quick to recognize. In 
all probability the other paroicous plants, which have been referred 
to N. hyalina, belong to Schiffner's new species, although this has not 
yet been definitely established. 
There is no sharp distinction between the leaves of N. hyalina and 
the perichaetial bracts (Figs. 1, 2). A general increase in size and 
especially in width is to be observed in most cases and often a greater 
degree of undulation, but these modifications are sometimes scarcely 
perceptible and even the innermost bracts may be essentially like 
the leaves. Bracteoles, except as an abnormality, are not developed. 
According to the descriptions the bracts in Nardia are more or less 
concrete with the perianth. This expression, however, is not wholly 
correct. There is really formed a shorter or longer perigynium in 
the form of a cup, upon the outer surface of which the bracts are borne. 
A similar but much deeper perigynium is characteristic of the genus 
Isotachis, as Goebel * has clearly shown. The margin of the cup, 
within the innermost bracts, gives rise to the actual perianth, the 
length of which tends to vary inversely with the height of the peri- 
gynium. In the case of N. hyalina the normal relation is figured by 
Maevicar On one side the cup is about a third the length of the 
perianth, on the opposite side about an eighth. This condition 
represents one extreme; in the var. heteromorpha (Gottsche) Schiffn., 
1 Brit. Hep. 37. 1874. 
? Leberm.-Stud. aus nórdl. Norwegen 38. 1892. 
*.Letos 88:320. 1910. ` 5 
4 Flora 96: 141. 1906. 
5 Student's Handb. British Hepatics 133. f. 5. 1912. 
