Evans: AIR CHAMBERS OF GRIMALDIA FRAGRANS 251 
The increase in the size of the chambers is due largely to the 
growth of the bounding cells and only slightly to further splittings 
of cell walls. The system of united cell plates in the dorsal cham- 
bers and the partitions between the chambers increase in vertical 
height simultaneously. Direct outgrowths from the surfaces of 
cell plates play a very small part in the process of subdivision. 
The material upon which this investigation was based was col- 
lected and prepared by Mr. John F. Logan, who expected to 
utilize it in his own studies. Through the pressure of other work 
his plans could not be realized, and his preparations were placed 
at the disposal of the writer for examination. The writer would 
therefore express his sincere thanks to Mr. Logan for his courtesy. 
SHEFFIELD SCIENTIFIC SCHOOL, 
YALE UNIVERSITY 
LITERATURE CITED 
_ Barnes, C. R., & Land, W. J. G. Bryological papers. I. The 
origin of air chambers. Bot. Gaz. 44: 197-213. Ji 22. . 1907. 
2. Black, C. A. The morphology of Riccia Frostii, Aust. Ann. Bot. 
27: 511-532. pl. 37, 38. 1913. 
Deutsch, H. A study of Targionia hypophylla. Bot. Gaz. 53: 
492-503. f. I-13. 1912. 
4. Hirsh, P. The development of the air chambers in the Ricciaceae. 
Bull. Torrey Club 37: 73-77- f. 1-6. 1910. 
Massalongo, C. Le Marchantiateas” della Flora Europea. 
Atti R. Ist. Veneto 75: 669-816. pl. 1-27. I91 
Miiller, K. Die Lebermoose Deutschlands, Oesterreichs u. d. 
Schweiz. In L. Rabenhorst, Kryptogamen- -Flora, ed. 2, 6. 
Leipzig. 1906-II. 
O’Keeffe,L. Structure and ot of Targionia hypophylla. 
New Phytol. 14: 105-116. f. I, 2 15. 
Pietsch, W. Entwicklungsgeschichte eb vegetativen Thallus, 
insbesondere der Luftkammern der Riccien. Flora 103: 347- 
484. f. I-21. {Orr 
g. Schiffner, V. Aaepholopteclie und biologische Untersuchungen 
iiber die Gattungen Grimaldia und Neesiella. Hedwigia 47: 
306-320. pl. 8. 1908. 
Stur, A. M. A aoe Aytonia. Bot. Gaz. 61: 48-58. pl. 
1-4 + f. 30-33- 
. Stephani, F. ae an [In Species Hepaticarum 1: 89- 
93.] Bull. Herb. Boissier 6: 792-796. 1898. 
i 
“ 
Py 
ai 
- 
9 
bn 
_ 
