Floral Ontogeny of Five Species of Talinum and of Related Taxa (Portulacaceae)

摘要

The floral development of five species of Talinum is studied. Each flower is surrounded by two involucral bracts. The perianth consists of five tepals initiated in a 2/5 phyllotaxis. In all species studied a first whorl of 10-13 stamens is initiated,except in T. napiforme where this whorl is reduced to five stamens. In multistaminate androecia, additional whorls develop centrffugally. In T. paniculatum, T. portulacifolium and T. napiforme the first stamens are initiated in pairs opposite the outer tepais. In several flowers of T. paniculatum and T. portulacifolium ten stamens are incepted in spiral sequence resembling diptos-temony. Similar ontogenetic patterns are present in several species of Phytolacca. However, within the genus Talinum the ontogenetic pattern of the firstly initiated stamens is not consistent with traditional diplostemony. !n T. triangulars the firstly initiated stamens are incepted in sectors on a ring meristem, resembling the early inception in several species of Anacampseros and Portulaca. The nectaries are associated with the filament bases and can be defined as caducous nectaries of the staminal type. The development of the tricarpellate, syncarpous gynoecium is very similar in all species studied; it is characterised bya Septate carpel-form.