Development of the hypanthium and androecium in New Zealand Myrtoideae (Myrtaceae)

Abstract

Floral organogeny and stamen development are described for three species of New Zealand Myrtoideae not examined previously: Lophomyrtus bullata, L. obcordata, and Neomyrtus pedunculata. The flowers have numerous stamens, which are initiated on the flank of an invaginated floral apex. The stamen primordia are initiated relatively early after petal initiation and continue to initiate on the flank until all of the space is occupied. The hypanthium has a critical role in the development of antesepalous stamens and their direction of growth in the mature flower. The hypanthium also has a role in the final position of the petals and sepals in the mature flower. This work supports the current view that floral architecture in the Myrtaceae is the result of timing and duration of stamen initiation and the enlargement of the hypanthium. This is the first in‐depth study of floral development in fleshy‐fruited Myrtaceae.

Keywords:

• androecium
• floral development
• hypanthium
• Lophomyrtus
• Myrtaceae
• Myrtoideae
• Neomyrtus
• stamen initiation