Department of Botany, Graduate School of Science, Kyoto University, Kyoto 506-8502, Japan.
J Plant Res. 2012 May;125(3):361-9. doi: 10.1007/s10265-011-0450-x. Epub 2011 Sep 9.
Cardiopteris, a small herbaceous genus, had long been placed in its own family, Cardiopteridaceae. However, the family was recently broadly circumscribed to include more genera in Aquifoliales. To better understand the morphological relationships of the genus and the family, I studied the floral anatomy and development of Cardiopteris using C. quinqueloba. As has been previously described, flowers are 5-merous with a unilocular gynoecium. I confirmed that the gynoecium is bicarpellate, possessing two dissimilar styles. An analysis of the development, structure, and vasculature of the gynoecium showed that it is pseudomonomerous, consisting of one fertile adaxial carpel and one solid sterile abaxial carpel. The adaxial carpel forms a thin style with a capitate stigma, whereas the abaxial carpel has a thick style, which develops into a freshy fruit appendage. Comparisons with flowers of other genera (Citronella, Gonocaryum, and Leptaulus) of Cardiopteridaceae as well as the other families (Aquifoliaceae, Helwingiaceae, Phyllonomaceae, and Stemonuraceae) of Aquifoliales showed that the pseudomonomerous gynoecium is very likely a synapomorphy to support the sister-group relationship between Cardiopteridaceae and Stemonuraceae. Moreover, contrary to all previous descriptions, Cardiopteris flowers were found to have an annular nectariferous disk at the base of the gynoecium.
扇蕨属是一个小型草本属，长期以来一直被置于其自身的扇蕨科中。然而，该科最近被广泛定义为包括冬青目更多的属。为了更好地理解该属和科的形态关系，我使用 Cardiopteris quinqueloba 研究了扇蕨的花部解剖结构和发育。如前所述，花为 5 数，具单室雌蕊。我证实了雌蕊是二心皮的，具有两个不同形状的花柱。对雌蕊的发育、结构和脉管系统的分析表明，它是假单体的，由一个可育的背腹心皮和一个实心的不育背心皮组成。腹心皮形成一个具头状柱头的薄花柱，而背心皮有一个厚的花柱，它发育成一个新鲜的果实附属物。与扇蕨科的其他属（香茅属、Gonocaryum 和 Leptaulus）以及冬青目其他科（冬青科、卫矛科、鳞叶木科和苦皮藤科）的花进行比较表明，假单体的雌蕊很可能是一个支持扇蕨科和苦皮藤科姐妹群关系的同源特征。此外，与之前的所有描述相反，发现扇蕨花在雌蕊基部有一个环状蜜腺盘。
