On the Position of the Genera Carlemannia Benth. and Sylviantus Hook. f.

In the Rubiaceae corolla and androecium are, as a rule, isomerous. In the genus Praravinia Korth., however, the number of stamens has been said to be double the number of the corolla lobes, and of several other genera species have been described in which the stamens should outnumber the corolla lobes; where I could reinvestigate the materials on which these statements had been based, i.e. in almost every case, I have, on the contrary, always found a perfectly regular alternation between the corolla lobes and the stamens. In two genera, to wit Carlemannia Benth. and Sylvianthus Hook. f., on the other hand, the number of stamens is indubitably smaller than the number of corolla lobes. If these genera are rightly referred to the Rubiaceae, they would form, therefore, real exceptions to the rule. The position of these plants with their dentate or serrate leaves and rudimentary stipules, however, is by no means sure. As a matter of fact, Solereder (Bull. Herb. Boiss. I, p. 173— 178, 1893) already long ago has transferred them, as a result of his anatomical studies, to the Caprifoliaceae. H a 11 i e r (Just’s Jahresber. XXXVI, 3, p. 221, 1910) put them in the Gesneriaceae, and a year later (Meded. Rijksherb. 1911, p. 40) in the Saxifragaceae, but in a note subsequently written on one of the sheets in the Leiden Herbarium he once more changes his opinion, and confesses himself converted to S o 1 e r e d e r’s point of view. To my mind too the affinity with the Caprifoliaceae is quite plausible: the strong reduction in the androecium, though unknown in the family itself. occurs in the nearly related Valerianaceae.