Comparative floral structure and systematics in Oxalidales (Oxalidaceae, Connaraceae, Brunelliaceae, Cephalotaceae, Cunoniaceae, Elaeocarpaceae, Tremandraceae)

Abstract

Floral morphology, anatomy and histology were studied in representatives of all families of current Oxalidales, which were recently constituted as a result of molecular systematic studies by other authors, and are composed of families of different positions in traditional classifications (Oxalidaceae, Connaraceae, Brunelliaceae, Cephalotaceae, Cunoniaceae, Elaeocarpaceae, Tremandraceae). Two of the three pairs of sister (or nested) families that come out in molecular analyses are highly supported by floral structure: Oxalidaceae/Connaraceae and Elaeocarpaceae/Tremandraceae, whereas Cephalotaceae/Cunoniaceae are not especially similar at the level of Oxalidales. Oxalidaceae and Connaraceae share petals that are postgenitally united into a basal tube (although they are imbricate in both) but free at the insertion zone, stamens that are congenitally united at the base, uniseriate glandular hairs on the stamen filaments, and ovules that are hemianatropous to almost orthotropous. The sharing of a special type of sieve‐tube plastids and of trimorphic heterostyly, studied by other authors, should also be mentioned. With Brunelliaceae, the two families share an androgynophore and nectaries at the base of the stamens in alternisepalous sectors. Elaeocarpaceae and Tremandraceae share buzz‐pollinated flowers and a syndrome of features functionally connected with it. In addition, petals are larger than sepals in advanced bud, they are valvate, involute and enwrap part of the adjacent stamens, they have three vascular traces. Lignified hairs are common on the anthers and are found in the ovary locules and on the ovules (not lignified) of representatives of both families. Ovules have a chalazal appendage, and the inner integument is much thicker than the outer. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140, 321–381.

Evidence for convergent evolution among phylogenetically distant rare species of Tetratheca (Elaeocarpaceae, formerly Tremandraceae) from Western Australia

“…Recent molecular studies (e.g. Savolainen et al 2000;Soltis et al 2000;Bradford and Barnes 2001;Crayn et al 2006) have indicated that Tremandraceae is nested within Elaeocarpaceae (Oxalidales) and the results of studies of floral morphology, anatomy and histology (Matthews and Endress 2002) are consistent with this relationship. Therefore Tremandraceae has been included in Elaeocarpaceae in recent classifications (Stevens 2001;The Angiosperm Phylogeny Group 2003;Coode 2004).…”

Genetic effects of rainforest fragmentation in an early successional tree (Elaeocarpus grandis)

“…Not much is known about Elaeocarpus pollinators, but recent studies suggest that their flowers require buzz pollination (Matthews and Endress, 2002).…”

Beyond pollination: diversity of secretory structures during flower development in different legume lineages

“…The occurrence of mucilaginous cells has been little studied in flowers despite its potential systematic value for the groups in which they occur (see Matthews et al 2001;Matthews & Endress 2002;. The presence of this cell type, known as 'special mucilage cells' (according to Matthew & Endress 2006), has been seldom reported in the literature and, in Leguminosae, it was previously recorded in the sepals of Amherstia species (Caesalpinioideae s.l.).…”