452 BOTANICAL GAZETTE [JUNE 
these the lowest cell forms the foot, the next one the seta, and 
the upper two the capsule. 
3. The sporogenous tissue is formed relatively early in the 
history of the sporophyte. 
4. In the development of spore mother cells and elaters 
the walls around the sporogenous cells become mucilaginous, the 
protoplasts of the former assume an amoeboid form and finally 
become large and spherical, while those of the latter are slender and 
elongated. A new cell wall is laid down around both spore mother 
cells and elaters. 
5. The assumption of an amoeboid form by the young spore 
mother cells is a feature related to their nutrition. 
6. An elater in Reboulia is homologous with a single spore 
mother cell, and not with a row of them. 
7. The exine and intine are differentiated in the tetrad stage, 
and the epispore has begun to develop. The formation of a double 
spiral band on the elaters is accompanied by a condensation and 
ultimate disappearance of the protoplasm. 
8. The short seta and bulbous foot are primitive features of 
the genus. 
St. LAWRENCE UNIVERSITY 
Canton, N.Y. 
LITERATURE CITED 
1. CAMPBELL, D. H., Mosses and ferns. New York. 1905. 
2. CavERS, F., Contributions to the biology of the Hepaticae. Part I. Tar- 
gionia, Reboulia, Preissia, Monoclea. Leeds and London. 1904. 
3- DurRaAnp, E. J., The development of the sex organs = seen at of 
Marchantia polymorpha. Bull. Torr. Bot. Club 35:321- . 
4. Haupt, A. W., A morphological study of Pallavicinia Lyell. Bot. GAz. 
66: 524-533. 1918. 
, Gametophyte and sex organs of Reboulia hemisphaerica. Bot. GAZ. 
71:61-74. 1921. 
6. Kienttz-GERLorr, F., Vergleichende Untersuchungen iiber die Entwick- 
lungsgeschichte des Lebermoossporogons. Bot. Zeit. 32:161-172; 33°777- 
782. 1875. 
7- McCormick, FLorENcE A., A study of Symphyogyna aspera. Bot. GAZ. 
58:401-418. 1914. 
8. WoopBuRN, W. L., Preliminary notes on the embryology of Reboulia 
hemisphaerica. Bull. Torr. Bot. Club 46: 461-464. 1920. 
5. 
