178 Atkinson —A Monograph of the 
recognizes as of generic value. For one group he retained 
the name Lemanea Bory ; to the other he gave the name 
S acker ia. 
Ketel 1 recognizes these two natural groups, but considers 
them of subgeneric value only. 
While the structural characters of the plants clearly show a 
natural division, the reproductive organs present only minor 
variations. The structural differences alone do not seem of 
sufficient value to warrant the acceptance of more than one 
genus. However, for convenience of study and determination, 
as well as for the suppression of great confusion of species 
which has always resulted from a merely superficial know- 
ledge of the anatomy, it is well to emphasize the importance 
of this natural distinction into two groups. I shall there- 
fore retain Lemanea Bory, emend. C. A. Agardh, for all the 
species at present known, and reduce Lemanea Sir’dt. and 
Sacheria Sir’dt. to subgeneric position. 
The subject-matter of this work naturally groups itself into 
the following paragraphs : — 
I. Habitat. 
II. Morphology of the Plant-parts. 
III. Development. 
1 . Germination of the Spores. 
2. Development of the Protonema. 
A. Prostrate ( permanent ) form . 
B. Chan transia-form. 
3. Development of the Sexual Shoot. 
4. Development of the Reproductive Organs. 
IV. Fertilization and Development of the Car- 
pospores. 
V. Branching of the Sexual Shoot, 
VI. Systematic Part. 
The localities from which material has been obtained for 
S' 
1 Anat. Untersuchungen liber Le 77 ianea\ Mittheilungen aus clem naturwissen- 
schaftlichen Verein fiir N euvorpommern und Riigen in Greifswald, 1886. 
