Feb., 1923] 
STOUT-ALTERNATION OF SEXES 
65 
purely staminate or pistillate, Cleome spinosa is like most species which are 
in the transition stages toward dioecism. The alternate appearance of 
male, female, and hermaphroditic flowers in a raceme of course favors cross¬ 
ing, and when this alternation tends to be synchronous on all the branches 
of a plant, selfing is largely prevented except in the case of the hermaph¬ 
roditic flowers. 
In the spider flower, with its long flowering period and its alternation of 
maleness and femaleness in the racemes, it is evident that practically the 
whole vegetative feeding power of every plant is drawn upon for seed 
production. The conditions are markedly different, and we may consider 
them more highly adaptive to the demands of reproduction, than is the 
case in strictly dioecious plants in which seed production is confined to one 
of each pair of male and female plants. We may, perhaps, characterize the 
sex conditions in Cleome spinosa as effecting a sort of super-dioecism in that 
the conditions favor both reproduction and crossing for each individual. 
Certain points regarding the determination of sex in the flowers of 
Cleome spinosa are clear. The conditions illustrate well the fact that the 
morphological differentiations of sex are fundamentally an extension of the 
phenomena of somatic differentiations. The expressions of differential 
qualities in leaves, stems, and flowers, with further differentiation of calyx, 
corolla, pistil, and stamens, with still further differentiations of tissue within 
each, are all recognized as one-sided, qualitative, and alternative expressions 
in protoplasmic units that are alike and which still remain alike in funda¬ 
mental constitution. Even the physically qualitative division of germ 
plasm in the reduction divisions is found in regeneration experiments and 
in parthenogenesis not to be a direct and absolute condition in the alter¬ 
nation of generations. The theory of sex chromosomes decidedly fails in 
general application to plants, and even in animals, where its application 
seems most marked, sex is often intergrading and reversible, showing that 
there is alternative expression rather than alternative inheritance. 
In Cleome spinosa it is evident that there are rather special and perhaps 
very specific stimulating and inhibiting influences which regulate the 
development of the sex organs. Whether these influences are substantive 
or more of the nature of stimuli, their action is cyclic and decidedly alter¬ 
native. The results clearly show that sex of flowers is determined progres¬ 
sively as they are formed in response to regulation by internal biogenetic 
conditions. 
New York Botanical Garden 
LITERATURE CITED 
Banta, A. M. 1916. Sex intergrades in a species of Crustacea. Proc. Nat. Acad. Sci. 
2: 578-583. 
Goldschmidt, R., and Poppelbaum, H. 1914. Erblichkeitsstudien an Schmetterlingen II. 
Zeitschr. Ind. Abst.- Vererbungsl. 11: 280-316. 
