HYBRIDIZATION AND FLORAL VASCULARIZATION

Hillson, Charles J. (Pennsylvania State U., University Park.) Hybridization and floral vascularization. Amer. Jour. Bot. 50(10): 971–978. Illus. 1963.—The floral steles of 6 synthetic hybrid mints, representing the F 1 generation of a cross between Mentha spicata strain 199 and Mentha aquatica, were compared with each other and with the steles of the parents. Comparisons of the level of trace divergence, ovary wall vascularization, presence or absence of a nectary, and the nature of the gaps associated with dorsal carpellary bundles show that floral vascularization is an inherited character. Although slight male dominance is indicated in the hybrid steles, anatomical features of both parents are evident. Thus, while vascular tissue may be conservative when phylogenetic reduction of floral parts takes place through adnation and/or connation, stelar modification through hybridization is documented.