Inflorescence and floral ontogeny in Jasminum fruticans (Oleaceae)

Abstract

The inflorescence and floral ontogeny of the oleaceous tropical bush, Jasminum fruticans L. were studied using epi-illumination light microscopy and compared with other Oleaceae. The flowers are arranged in a thyrsoid inflorescence with a determinate pattern of development. Deviations from the common pathway of floral ontogeny in Oleaceae observed in J. fruticans are characterised by pentamery in calyx and corolla, diagonal position of sepals, some deviation from acropetal and simultaneous initiation of floral organs. Sepals are helically initiated, beginning with the abaxial sepal. Formation of petal lobes from the ring meristem also is not simultaneous with the initiation of three petals before the others. Concurrently with the formation of corolla ring, two stamens are initiated sequentially. Two median carpels are the last organs to be initiated. Unusual features of organ enlargement include the quincuncial-imbricate aestivation of the corolla and formation of trichomes on the distal portion of petals and stamens.