Morphological and ontogenetic studies on the gynostemium of some Australian members of Diuridae and Cranichideae (Orchidaceae)

Abstract

Gynostemium development of Genoplesium fimbriatum (Orchidaceae—Diurideae) is described and documented by means of SEM micrographs. Other Australian representatives of tribes Diurideae and Cranichideae are briefly treated. Particular attention is paid to the early stages which are essential for the correct interpretation of the gynostemium structure. It was found that gynostemium development largely conforms to that of the other Orchidaceae that have been examined in this respect. Several of the species have auricles (filament appendages) next to the anther and a shallowly or prominently three-lobed median stigma lobe in middle ontogeny which are both interesting similarities shared with tribes Orchideae and Diseae. As in the latter two tribes, the mature lateral gynostemium appendages ('column-wings') of some of the study species are of dual origin, comprising both a staminodial and an auricular element.