Reviews

This study is a full-sounding prelude to the fundamental work on the morphology of inflorescences, which is being prepared by Prof. Dr. W. Troll of Mainz. All inflorescences in Valerianaceae are understood as modifications of one basic form, the thyrse. It is gratifying to note that forms of inflorescences, described in systematical works as for instance 1) capitate or interruptedly spicate (Plectritis), 2) compound dichasium, dichotomous throughout (cymoid Valeriana spp.), or dichotomously branched inflorescence (Valerianella), 3) ‘rispig bis fast trugdoldig’ (Phuodendron), in reality all are variations on one theme, the decussate mono-, to pleiothyrse, i. e. a simple to compound inflorescence with a racemous primary axis and cymous lateral axes. The transformations take place first of all by a favoured development of lateral axes on definite heights of the main axis (‘basi-mesotoner, akrotoner Förderungssinn’) and secondly by the number of flowers developing and the more or less pronounced tendency to form monochasia. Moreover, different forms such as loose panicles, umbels, glomerules, heads and even nearly simple racemes (Aretiastrum), originate by extension or reduction of axes of some or all orders.