IOWA ACADEMY OF SCIENCE xv 
TABLE OF CONTENTS 
Letter of Transmittal VII 
Officers of the Academy IX 
Membership of the Academy X 
Table of Contents XV 
Report of the Secretary 1 
Minutes of the Twenty-First Meeting 2 
Treasurer’s Report 5 
Presidential Address, by C. O. Bates 7 
Iowa Erysiphaceae, by J. P. Anderson. 15 
Notes on the Algae of Iowa, by Robert Earle Buchanan. 47 
Homology of Tissues in Ferns, by Henry S. Conard 85 
A Study of the Variation of the Ray Flowers of Certain Compositae, by 
Winfield Dudgeon 89 
Studies in Karyokinesis, by James Ellis Gow 107 
Some Municipal Water Problems, by L. H. Pammel 115 
A Catalog of the Poisonous Plants of Iowa, by L. H. Pammel and Estelle 
D. Fogel 147 
Securing a Stand of Clover on the Southern Iowa Loess, by E. B. Watson 177 
Some Features of Iowa Ground Waters, by W. S. Hendrickson 187 
The Determination of Silica, by Nicholas Knight 201 
Some Features of the Channel of the Mississippi River Between Lansing 
and Dubuque, and Their Probable History, by Samuel Calvin 213 
Physiographic Significance of the Mesa De Maya, by Charles R. Keyes... 221 
Tertiary Terranes of New Mexico, by Charles R. Keyes 223 
Volcanic Phenomena About Citlaltepetl and Popocateptl, by Charles R. 
R. Keyes 229 
Exposures of Iowan and Kansan (?) Drift, East of the Usually Accepted 
Boundary Line of the Driftless Area, by Ellison Orr 231 
The Loess of the Missouri River, by B. Shimek 237 
Recent Alluvial Changes in Southwestern Iowa, by J. E. Todd 257 
Effects of Certain Characteristics of Rocks on Their Erosion, by J. E. Todd 267 
The Physical Science Laboratory of the State Normal, by A. C. Page.... 271 
Tne Innervation of the Lateral Line System of Amphiuma, by H. W. Norris 273 
Index 279 
Author’s Index 281 
