First report of chromosome numbers of the Carlemanniaceae (Lamiales)

The Carlemanniaceae comprises two small genera that are restricted to East Asia: the Carlemannia and Silvianthus. These genera were previously placed in the Rubiaceae or Caprifoliaceae, but are now considered a distinct family that is probably related to the Oleaceae in the Lamiales. The family is still poorly understood with respect to its morphological characteristics. Here, we present the first report of the chromosome numbers of the family using species from both genera, i.e., Carlemannia tetragona, Silvianthus bracteatus ssp. bracteatus, and S. bracteatus ssp. clerodendroides. The species were compared with the chromosome numbers of Oleaceae and associated families using a Bayesian tree that was generated from rbcL and ndhF sequence data from Genbank. C. tetragona had 2n = 30 (x = 15), whereas the two subspecies of Silvianthus had 2n = 38 (x = 19). Comparisons of chromosome numbers support the distinctness of the Carlemanniaceae, not only from the Oleaceae (x = 11, 13, 23), but also from the Tetrachondraceae (x = 10, 11), a family that is possibly related to the Carlemanniaceae and/or Oleaceae in the Lamiales. The notable difference in chromosome number between Carlemannia and Silvianthus, as well as the differences in other characteristics (pollen, seed, and fruit morphology), suggests that the family split early in its evolution.     

四角果科（Carlemanniaceae）的系统位置评述

四角果科（Carlemanniaceae）科下有四角果属Carlemannia（3种）和蜘蛛花属Silvianthus（1种1亚种）。这两属建立之初均置于茜草科,此后又被多个分类及系统学家将它们移至忍冬科;1965年由Airy Shaw将它们从忍冬科独立成四角果科,得到了部分学者的赞同,但其系统位置仍存在争议,认为与与苦苣苔科、虎耳草科、马鞭草科和绣球花科等科的关系错综复杂;科下两属间的关系也仍然值得探讨。APGII认为四角果科与木樨科素馨属或女贞属近缘,但支持率不高。本文对四角果属和蜘蛛花属系统位置的研究和现状进行了评述;将Silvianthus bracteatus ssp. tonkinensis (Gagnep.) H. W. Li作为线萼蜘蛛花Silvianthus bracteatus ssp. clerodendroides (Airy Shaw) H.W.Li的异名归并;并对今后的研究提出了建议。