Open AccessComparative floral structure and systematics in O chnaceae s.l. ( O chnaceae, Q uiinaceae and M edusagynaceae; M alpighiales)
Author(s) -
Matthews Merran L.,
Amaral Maria Do Carmo E.,
Endress Peter K.
Publication year - 2012
Publication title -
botanical journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.872
H-Index - 68
eISSN - 1095-8339
pISSN - 0024-4074
DOI - 10.1111/j.1095-8339.2012.01299.x
Subject(s) - biology , sepal , gynoecium , perianth , petal , pedicel , ovule , botany , locule , ovary , synapomorphy , stamen , phylogenetics , pollen , clade , biochemistry , gene , endocrinology
O chnaceae s.l. ( O chnaceae, Q uiinaceae and M edusagynaceae), one of the well‐supported subclades of the large order Malpighiales retrieved so far in molecular phylogenetic studies, were comparatively studied with regard to floral structure using microtome section series and scanning electron microscopy ( SEM ). Floral morphology, anatomy and histology also strongly reflect this close relationship. Potential synapomorphies of the subclade include: flowers nectarless, sepals of different sizes within a flower, petals not retarded in development and forming the protective organs of advanced floral buds, petal aestivation contort, petals with three vascular traces, petals reflexed over the sepals and directed toward the pedicel, polystemony, anthers almost or completely basifixed, gynoecium often with more than five carpels, short gynophore present, styles separate for at least their uppermost part and radiating outwards, suction‐cup‐shaped stigmas, vasculature forming a dorsal band of bundles in the upper stylar region, gynoecium epidermis with large, radially elongate cells, ovules either weakly crassinucellar or incompletely tenuinucellar with an endothelium, abundance of tanniferous tissues and sclerenchyma in floral organs. The most strongly supported subclade of two of the three families in molecular analyses, Q uiinaceae and M edusagynaceae, is also particularly well supported by floral structural features, including the presence of functionally and morphologically unisexual flowers, a massive thecal septum that persists after anther dehiscence, styles radiating outward from the ovary, two lateral ovules per carpel, positioned one above the other, conspicuous longitudinal ribs on the ovary wall at anthesis, and a ‘false endothelium’ on the nucellus at anthesis. Additionally, the group fits well in M alpighiales and further emphasizes the relationship of M alpighiales with C elastrales and O xalidales, and thus the unity of the COM clade. © 2012 The L innean S ociety of L ondon, B otanical J ournal of the L innean S ociety , 2012, 170 , 299–392.