THELIGONUM CYNOCRAMBE - DEVELOPMENTAL MORPHOLOGY OF A PECULIAR RUBIACEOUS HERB

The annual Mediterranean herb Theligonum cynocrambe shows a peculiar c ombination of morphological characters, e.g., switch from decussate to spiral phyllotaxis with 90-100 degrees divergence, combined with a ch ange from interpetiolar to lateral stipules, anemophily, lack of calyx , flowers often dimerous to trimerous, corolla fused in both male and female flowers, male flowers extra-axillary, with 2-19 stamens per flo wer, female flowers axillary, with inferior uniovulate ovary, basilate ral style and perianth, nut-like fruits with elaiosome. In male flower s the androecium emerges as an (uneven) elliptical rim with a central depression. This common girdling primordium is divided up into several stamen primordia. In male flowers with low stamen number the stamen p rimordia may occupy the corners alternating with the corolla lobes. Th ere are no epipetalous androecial primordia that secondarily divide in to stamens. Male flowers occasionally show a hemispherical base that m ay be interpreted as remnant of the inferior ovary. In female flowers a ring primordium grows into a tube on which the petal lobes arise. Th e perianth and style become displaced adaxially by uneven growth of th e inferior ovary. The ovary is basically bilocular. The lower region o f the ovary is provided with a septum that is overtopped and hidden by the single curved ovule. Theligonum is referred to the Rubiaceae-Rubi oideae, with the Anthospermeae and Paederieae as most closely related tribes.