DupLeR: AIR CHAMBERS OF REBOULIA 251 
THE MALE RECEPTACLE 
The tissue of the male receptacle is compact, aside from the 
antheridial chambers and very few air chambers appear on the 
disc. These are situated along the margins and are relatively 
simple in structure, containing only simple pores. In this respect 
the writer’s observations agree with those of Haupt (9) but differ 
from those of Cavers (4, 5), who described and figured small 
barrel-shaped pores in the male receptacle of Reboulia hemi- 
sphaerica. 
SUMMARY 
The very elongated air chambers of the thallus extend length- 
wise along the midrib region and from this radiate pinnately 
toward the margins of the thallus. . 
The air chamber tissue consists essentially of a single series 
of oblique chambers extending from the surface to the compact 
tissue, overlapping one another shingle-like and thus giving the 
appearance in section of several series of superimposed chambers. 
The primary chambers are extensively subdivided into partial 
secondary chambers by plates of cells arising as lateral outgrowths 
of the primary walls. 
The air chambers of both thallus and receptacles originate by 
splitting of cell membranes, the splits arising both internally and 
superficially, and generally proceeding from both points of origin 
simultaneously. . 
The later development of the chambers and the secondary 
partitioning is due largely to growth of the tissues, further splitting 
apparently playing but a small réle in the process. 
JuNIATA COLLEGE, 
HUNTINGDON, PENNSYLVANIA 
LITERATURE CITED 
1. Barnes, C. R., & Land, W. J. G. Bryological papers. I. The 
origin of air chambers.» Bot. Gaz. 44: 197-213. f. I-22. 1907. 
2. Black, C. A. The morphology of Riccia Frostit, Aust. Ann. Bot. 
27: 511-532. pl. 37, 38. 1913. 
3. Campbell, D. H. Mosses and Ferns. 3d ed. New York. 1918. 
4. Cavers, F. Contributions to the biology of the Hepaticae. Part I. 
Targionia, Reboulia, Preissia, Monoclea. Leeds and London. 
1904. 
