202 BOTANICAL GAZETTE [MARCH 
expression under any ordinary environmental conditions. The only 
other available hypothesis, according to the writer’s views, would be 
to assume that sex is not determined in the seed, but only after 
vegetative growth has begun. 
The ratio between carpellate and staminate plants is 1:1, with 
considerable fluctuation in either direction for any given planting. 
The vegetative dimorphism is the same for individuals which show 
no tendency to change their sexual expression and those which do 
so sooner or later. The main sexual differences are as follows. 
Carpellate plant.—A broad flat crown of leaves; vigorous 
appearance but not so tall as the staminate plant; robust stem; 
large root system; large leaf blades with more numerous leaflets, 
usually five or more; terminal inflorescence usually leafy; petioles 
longer and more robust; carpellate flowers with the perianth a 
closed sacklike sheath with no vestigial stamens; weight at begin- 
ning of the flowering period nearly twice as much as that of the 
staminate plant of the same age; a longer period of life and growth. 
Staminate plant.—A slender, spindling habit and taller than 
the carpellate plant through the very rapid elongation of the 
internodes just before anthesis; root system smaller than in the 
carpellate plant; smaller leaf blades with fewer leaflets; shorter 
and more slender petioles; terminal inflorescence with few or no 
leaves; staminate flowers with 3-6 separate sepals (usually 4 or 5) 
with no vestige of a gynoecium; weight about half that of the 
carpellate plant at time of anthesis; a much shorter life than the 
carpellate plant. 
The weights of a dozen individuals of the same age, from the 
same plot, were determined as follows. Staminate and carpellate 
plants were cut off at the cotyledon node and immediately placed 
in glass jars with ground glass stoppers. They were thus weighed 
without loss of water. After weighing, the stoppers were removed 
and the jars with the specimens kept in the oven at 50°C. After 
three days they were placed in an oven at 110°C. and heated for 
two hours. The stoppers were then replaced, and after cooling 
the final weights were made of the dried plants. Table I gives 
the individual weights, the totals, and the averages. It will be 
seen that the carpellate plants average nearly twice the weight 
