MAY 14 1QIW 
"The Ohio T^aturalist, 
PUBLISHED BY 
The Biological Club of the Ohio Slate University. 
liBRAS 
NEW YC 
BOTANK 
garde 
Volume IX. 
MAY, 1909. 
No. 7. 
TABLE OF CONTENTS 
Sauer— Nuclear Divisions in the Pollen Mother Cells of Convallaria Majalis L. 497 
Schaffner—C hromosome Difference in Asoaris megalocephala. 506 
Parker— The Catalpa Leaf Spot. 509 
(Iriggs— A Note on A mitosis by Constriction in Synchytrium. 513 
Foerste— The Bedford Fauna at Indian Fields and Irvine, Kentucky. 515 
McCray—M eeting of the Biological Club.. 524 
NUCLEAR DIVISIONS IN THE POLLEN MOTHER-CELLS OF 
CONVALLARIA MAJALIS L. 
Louis W. Sauer. 
The significance which recent investigators have read into the 
two maturation divisions, as well as the peculiar behavior of the 
chromatic substance during and after synapsis, make the 
chromosome the cynosure of all the problems in heredity. 
Although the Liliaceae have served as a classical group of 
angiosperms for this kind of work in botanical research, only 
twice have their closest allies, the Convallariaceae, received 
attention. Strasburger (’88) in a very general way, refers to the 
chromosomes of Convallaria, and Weigand (’99, ’00) takes up the 
development of the microsporangium, and of the embryo sac of 
Convallaria, but little emphasis is laid on the nuclear divisions in 
the pollen mother-cells. Weigand holds that the reduced 
number of chromosomes is eighteen, that he could not determine 
the plane of the first nuclear division of the mother cell, and that 
the plane of the second division appears to be transverse. He 
further states that at several instances the chromatin behaves 
peculiarly, and that the generative cell of the pollen grain is cut 
off shortly before the flower opens. 
The present writer undertook a careful study of the nuclear 
phenomena of the pollen mother-cells of Convallaria majalis L, 
with the hope of making further contribution towards the solu¬ 
tion of the problem of heredity and the chromosome. With 
none of the above mentioned observations of Weigand does the 
present writer agree. This paper is offered as a preliminary to 
further work on the chromosome. 
To Professor Guyer, at whose suggestion the work was under¬ 
taken, the writer is much indebted for valuable assistance. 
497 
