FLORAL ONTOGENY OF 5 SPECIES OF TALINUM AND OF RELATED TAXA (PORTULACACEAE)

The floral development of five species of Talinum is studied. Each flo wer is surrounded by two involucral bracts. The perianth consists of f ive tepals initiated in a 2/5 phyllotaxis. In all species studied a fi rst whorl of 10-13 stamens is initiated, except in T. napiforme where this whorl is reduced to five stamens. in multistaminate androecia, ad ditional whorls develop centrifugally. in T. paniculatum, T. portulaci folium and T. napiforme the first stamens are initiated in pairs oppos ite the outer tepals. In several flowers of T. paniculatum and T. port ulacifolium ten stamens are incepted in spiral sequence resembling dip lostemony. Similar ontogenetic patterns are present in several species of Phytolacca. However, within the genus Talinum the ontogenetic patt ern of the firstly initiated stamens is not consistent with traditiona l diplostemony. In T. triangulare the firstly initiated stamens are in cepted in sectors on a ring meristem, resembling the early inception i n several species of Anacampseros and Portulaca, The nectaries are ass ociated with the filament bases and can be defined as caducous nectari es of the staminal type. The development of the tricarpellate, syncarp ous gynoecium is very similar in all species studied; it is characteri sed by a leptate carpel-form.