600 THE AMERICAN NATURALIST. [VoL. XXXII. 
In summing up the evidence obtained from a comparative study of 
the living and fossil Marattiacee, Professor Bower recognizes the 
difficulties in reaching positive conclusions. However, while admit- 
ting that any conclusions reached must be subject to modification, 
his own view (p. 69) is that the circular sorus, like that found in the 
fossil Asterotheca, probably is the primitive type from which the 
‘others have been derived. The difference in form of the sorus, 
especially the extreme elongation in Danza, is correlated with 
extension of the leaf surface. In another direction, by repeated 
constriction of the elongated sorus, the numerous scattered sori of 
Kaulfussia may have arisen. 
It is to be regretted that our author did not make a fuller com- 
parison of the Marattiacez and Ophioglossaceez. He expresses no 
opinion as to the affinities of the two, beyond calling attention to the 
resemblances between the sporangial spike of Ophioglossum and the 
elongated sorus of Danza, which resemblance he does not regard in 
the light of a true homology. 
We are promised a study of the Leptosporangiate which will be 
awaited with keen interest by all students interested in these most 
important problems, which bear directly upon the question of the 
origin of the flowering plants as well as the ferns. 
STANFORD UNIVERSITY, DovucLtas HOUGHTON CAMPBELL. 
1898 
ay, 
Recent Inexpensive Popular Literature on Mushrooms. — The 
following papers more or less useful to collectors and eaters of fleshy 
fungi have come to our table within the year: 
“Suggestions to Collectors of Fleshy Fungi,” by Prof. L. M. 
Underwood. Reprinted from Bul. 80 Alabama Agri. Exp. Station. 
Cambridge Bot. Supply Co., Cambridge, Mass., July, 1897. 14 PP- 
Price, 25 cents. 
“ Mushrooms and Their Use,” by Charles H. Peck, State Botanist 
of New York. 8vo, 80 pp., 32 cuts. Reprinted from Cultivator and 
Country Gentleman, Albany, N.Y., 1894. Cambridge Bot. Supply 
Co., May, 1897. Price, 50 cents. 
“ How to Grow Mushrooms,” by William Falconer. Farmers’ Bul- 
letin No. 53, Division of Vegetable Physiology and Pathology. U. S. 
Dept. of Agriculture, Washington, D. C., March, 1897. 8vo, 19 PP» 
14 figs. Free on application. ; 
“ Observations on Recent Cases of Mushroom Poisoning in the 
District of Columbia,” by F. V. Coville. Circular No. 13. 
