54 Correlation between Somatic Characters and Fertility 
Material. 
The involucral bracts of Hibiscus seem particularly adapted for an investigation 
of the relationship between a somatic character and fertility. 
Without having as far as we know any important physiological relationship to 
the essential organs of the flower, the involucral whorl is nevertheless in the closest 
ontogenetic association with them*. 
Diagrams of involucral whorls of Hibiscus. Figures 1 and 2 show involucre in situ with the calyx and 
matured fruit; others show involucre only. Fig. 1, H. moscheutos ; fig. 2, H. syriacus ; fig. 3, 
H. militaris ; fig. 4, H. trionum ; fig. 5, H. manihot. All are natural size. 
* This statement is meant to apply only to the species discussed in this paper and is not intended 
to exclude the ecological function of protection to the immature flower bud. In some species of plants 
the involucral whorl is so large and chlorophyllaceous that it may take some part in photosynthesis, 
possibly contributing sensibly to the development of the seeds. Again, in other forms the involucre 
may undergo extensive modifications during — and possibly in consequence of — the development of the 
fruit. In the species discussed neither of these possibilities need to be taken into consideration. The 
figures will make the structures perfectly clear. 
