|KONG, DONG-RUI - Ludong University|
|LI, LU - Southwest Forestry University|
|PENG, HUA - Kunming Institute Of Botany|
Submitted to: Plant Systematics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2017
Publication Date: 12/16/2017
Citation: Kong, D., Schori, M., Li, L., Peng, H. 2017. Floral morphology of Gonocaryum with emphasis on the gynoecium. Plant Systematics and Evolution. https://doi.org/10.1007/s00606-017-1479-7.
Interpretive Summary: We studied flower development of Gonocaryum, a group of shrubs and trees in Southeast Asia, because it is related to Cardiopteris, a liana with many unusual reproductive features. We used a scanning electron microscope and slides of buds and flowers to examine development and compared the features to those of Cardiopteris and other closely related groups (hollies and relatives). Several features, including an ovary that forms by fusion of three separate parts, are shared by all members of the Cardiopteris family, but only Gonocaryum has unisexual flowers. Reproductive features in the hollies and relatives are poorly known, so this study helps to fill in gaps in our understanding of how they differ from other flowering plants and shows which features are unique to Cardiopteris.
Technical Abstract: We investigated the floral development of Gonocaryum, a genus of Cardiopteridaceae that was segregated from Icacinaceae s.l., using scanning electron microscopy to clarify its gynoecial structure and facilitate morphological comparisons of Cardiopteridaceae. The key floral developmental characters include sepal initiation that follows a quincuncial spiral sequence; petals that are valvate with inflexed tips and connate bases; a petal and stamen initiation sequence that is more or less unidirectional; a globular protuberance on top of the connective; a tricarpellate, pseudomonomerous gynoecium with one carpel that develops a stigma while the other two each produce an ovule; and a unitegmic, anatropous ovule with an obturator on the funicle. The floral developmental characters of Gonocaryum are discussed relative to other genera of Cardiopteridaceae, primarily Cardiopteris, which has been well studied. The imbricate sepals that are basally connate, initiated in a quincuncial spiral sequence, and the tricarpellate, pseudomonomerous gynoecium are common characters of Cardiopteridaceae. Unisexual flowers are an autapomorphy of Gonocaryum in Cardiopteridaceae.