تكوين گل آذين و گل در گونه Phytolacca amaricana (سرخاب كولي)

The study of floral Ontogeny in Phytolacca americana

The inflorescence and floral ontogeny of Phytolacca americana have been studied using epi-illumination light microscopy. Our result revealed that flowers initiate acropetaly in racemous inflorescence with helical order. Each flower was subtended by a bract and two bracteoles. The perianth composed of 5 sepals which are formed helically in a 2/5 sequence. 10 stamens are arranged in five pairs opposite to sepals and their initiation follows sequential order. The number of carpels corresponds with the number of stamens in the inner androecial whorl. In mature flowers basal portion of the carpel became fused, while the distal portion, which contains style, remained free. Unusual characters that have been observed include: initiation of additional flowers at the base of bracts and bracteoles, formation of the extra stamens outside the inner stamens and doubling of inner stamens which result in increase of stamens and carpels. Our data in regard to the androecial ontogeny support existence of diplostemony as an ancestral type in the Phytolaccaceae, and therefore suggest that P. americana occupies a basal position in Phytolaccaceae.