1919] STOUT—INTERSEX ES III 
of the bog myrtle or sweet gale (Myrica Gale). This plant is a 
small shrub which grows abundantly in swamps and heaths in 
Europe, Asia, and the northern part of North America. The 
species is described as strictly dioecious, and until 1901 no obser- 
vations that it is ever otherwise have apparently been recorded. 
Davey and Gipson find that in the peat moors of England there 
are everywhere present intersexes, or, as they call them, ‘‘ mixed 
plants” of many gradations. Judged as a whole, the plants pre- 
sent every gradation of intersexes between dioecism, monoecism, 
and hermaphroditism. The variations seen in the various catkins 
on a single plant include the entire range, and all the grades may 
appear among the flowers of a single catkin. Furthermore, a 
study of individual plants for a series of years shows that changes 
of sex from year to year occur. Plants entirely female in 1913 
were entirely male in 1914. Plants female in 1913 were mixed in 
1914, entirely or nearly all male in 1915, and again female in 
1916, ; 
DAvEY and Gipson point out that the changes in sex Seen in 
Myrica Gale indicate that sex determination is here in some way 
associated with environmental conditions. In regard to this they 
state as follows: 
The conditions which naturally suggest themselves are moisture, tem- 
perature, and light (with their influence on nutrition), and also the previous 
state of a plant as regards the production of fruit. Since the staminate 
flowers are developed early in the season preceding that in which they flower, 
while the pistillate catkins develop much later, it is possible that conditions 
accelerating or retarding the development of catkin buds may influence the 
Proportions of the two kinds (pp. 150-151). 
The facts reported for Myrica Gale are striking and suggest 
that similar conditions may already be present or may spontane- 
ously arise in other species now considered as dioecious. 
Intersexes in Plantago lanceolata 
This species is a native of Europe and Asia. It has been 
introduced into America, where it has spread from the Atlantic 
to the Pacific, through Canada, and southward in the United 
States to Florida. It is well known as a vigorously growing 
species which in many sections has become a troublesome weed. 
