1910] CURRENT LITERATURE "393 
where the surface overwash has hidden the character of the substratum. The 
forest on the loess is dominated by Quercus alba and Q. ruba, while the adjacent 
sandy areas are covered by the more xerophytic Q. velutina and Q. macrocarpa.— 
Gro. D. FULLER 
Air chambers of Ricciaceae.— Miss Hrrsu,3‘ under the direction of Dr. E. J. 
URAND, has examined a number of species of Riccia to determine the correctness 
of the statement of BARNES and Lanp that the air chambers of Marchantiales 
arise invariably by the splitting of internal walls. She finds that in the Ricciaceae 
the statement is true only for Riccia natans and Riccia fluitans, and that in all 
other species which she examined the air chambers arise according to the method 
described by LErtcEs, and cites as proof three figures of Riccia Frostii. To 
critical students of the group these figures do not furnish conclusive evidence one 
way or the other, for they are made in such a manner that the relation to each 
other of the rows of the cells back of the growing point cannot be made out with 
any certainty. In fig. 4 of Riccia Frostii the first air chambers can as easily be 
interpreted as having split from within the thallus and having just reached the 
surface, as that the cells have become papillate. In fact, the contour of the section 
drawn seems to show that all the filaments actually originated by splitting and 
intercalary growth. The same is true in a more marked degree of fig. 5, and less 
So of fig. 6. In the latter figure the arching of the superficial cells due to turgor is 
interpreted by Miss Hrrsu as the beginning of the papillate outgrowths of Lerr- 
GEB. Such investigations should be preceded by a careful study of the develop- 
ment of the thallus from the growing point, and there should be a clear conception 
of the arrangement of the cells which result from this growing point. While the 
Style of the drawings is admirable, the position of cells and cell walls shows that 
such study must have been neglected in this case —W. J. G. LAN. 
Light and germination.—KinzeL3? has devised apparatus that answers all 
objections to his former methods, which indicated that light favored or was even 
necessary for the germination of various seeds. Both illuminated and darkened 
after-ripened seeds of Veronica Anagallis were kept in germinators at a constant 
temperature of 1627C. Within a week 100 per cent of the illuminated cultures 
had germinated, while none of the darkened ones grew even after three months. 
He lists 63 species that germinate only in light, of which the following are examples: 
Scheuchzeria palustris, Luzula albida, Thalictrum angustifolium, T. aquile- 
Siifolium, Drosera rotundifolia, D. anglica, D. intermedia, Primula pubescens, 
P. spectabilis, Verbascum Thapsus, V. nigrum, Mimulus luteus, Veronica Anagal- 
lis, and Campanula rotundijolia. He does not state whether high temperatures 
will dispose of the necessity of light, as is the case with various fern spores. Italso 
* HirgsH, Pavutine E., The Ey of air chambers in the Ricciaceae. 
Bull. Torr. Bot. Club 37:73-77. figs. 6. 
3? KINZEL, W., Lichtkeimung: aes und Erginzungen. Ber. Deutsch. 
Bot. Gesell. 27:536-545. pl. 19. 1909 
