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 Hibitcut. Figures 1 and 2 show involucre in titu with the calyx and matured fruit; others show involucre only.

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... ig. 1, S. moteheutot; fig. 2 , S. rt/riaau; fig. 3, H. militaris; fig. 4, H. trionum ; fig. 5 , 3. ma-nihot. All are natural size.