GENETICS: J. ZINN 
507 
Dimorphism manifests itself in two externally different forms. The 
different characteristics may appear simultaneously distributed in the 
organs of the same individual as in Trifolium pratense quinquef olium De 
Vries or in V eronica agrestis; in another group of plants each individual 
of the race may display only one of the dimorphic characters as in the 
case of certain strains of Mat thiol a, Antirrhinum, Dipsacus sylvestris 
torsus, etc. 
In interpreting these phenomena, De Vries whose investigations 
involved a great abundance of material, assumes the peculiar behavior of 
these races to be due to the interaction of two antagonistic, mutually 
exclusive characters." The operation of these two contending charac- 
ters within the individual leads to the formation of two distinct groups 
of plants, the half-races and the middle races or ever-sporting varieties. 
Opposed to this interpretation is the view held by certain writers who 
consider the ever-sporting nature of many of these races as mere 
somatic variations and relegate them into the group of non-heritable 
modifications. 
More recently, however, some of the ever-sporting types in plants as 
well as in animals have been subjected to a genetic analysis and their 
peculiar mode of inheritance has been explained on Mendelian grounds. 
The purpose of the present communication is to record the results of 
a study on a highly variable, ever-sporting race which I have discovered 
in Fagopyrum tataricum Gaertn. (Polygonum tataricum Linn.). In the 
course of observations on this race my attention was chiefly devoted to 
the study of variation and transmission of the external characters in an 
endeavor first to estabKsh by direct experiment the behavior of this race 
under different conditions before attempting an analysis of the underly- 
ing genetic causes. 
The full account of this investigation will be published in Genetics. 
Material and experimental methods. — The race with which the present 
account is concerned originated from commercial fruits of Fagopyrum 
tataricum, Tartary Buckwheat, which had grown in Maine. In a popu- 
lation of several hundreds of plants, one plant was found to be distin- 
guished by a particularly high degree of variability in the structure of 
its flow^ers. This plant was selected as a starting point of a strict pedi- 
gree culture, and since its isolation in 1916 five generations have been 
grown. The study of floral variations of this race involved the exami- 
nation of more than 57,000 flowers and fruits. 
The manifestation of variations of this race was studied under different 
conditions of environment. The cultures grew in pots under greenhouse 
