XVI International Botanical Congess

In cladistic analyses Gymnostachys appears as sister to Araceae (Mayo et al.) or (together with Acorus) as sister to all other monocots (Davis). In comparative studies on flower morphology Gymnostachys turned out to differ from other Araceae and Acorus, but to show similarities with Potamogetonaceae: the gynoecium consists of an ascidiate, stipitate carpel with a single pendent ovule, basal flower vasculature forms a central complex (but also in Acorus) instead of single vascular traces for each organ, basal gynoecium vasculature is in a diagonally tetramerous pattern, the stigma is dry at anthesis (Hay). There are several gynoecial features of Gymnostachys differing from other Araceae, Potamogeton and Acorus (single carpel, unitegmic ovule, vascular elements not organized into distinct vascular bundles in the carpel).