The morphology and relationships of the Sphaerosepalaceae (Malvales)

摘要: The comparative vegetative and reproductive morphology anatomy of the Malagasy endemic family Sphaerosepalaceae is examined in light two current competing hypotheses relationship from recent molecular studies. are similar to Thymelaeaceae on basis leaf architecture, calyx vasculature having endostomal micropyles. Comparisons with Tepuianthus subfamily Octolepidoideae drawn seed structure, indument type, perianth structure pollen. Resin-filled, sclerenchymatous idioblasts, floral (positional) monosymmetry, a single series stamen trunk bundles well-developed bixoid chalaza Dialyceras parvifolium link its other putative sister group: clade containing Bixaceae, Cochlospermaceae Diegodendraceae. Synapomorphies include: fused, intrapetiolar stipules, embryo pollen endoapertures encompassing ectoapertures tetramerous perianth. extremely apical septum eusyncarpous gynoecium Rhopalocarpus suggests that gynoterminal style present this genus has been secondarily derived an ancestor fully syncarpous, basistylous gynoecium, as Dialyceras. morphological evolutionary nature apically septate gynoecia discussed. A rosette arrangement ovules each carpel coccus D. coriaceum expands bauplan concept probably unique among angiosperms whole. © 2004 Linnean Society London, Botanical Journal Society, 2004, 144, 1–40.