Les inflorescences des Melastomataceae guyanaises, leur filiation et leur valeur taxonomique

Abstract

Analysis of the inflorescence structures of 188 species from French Guyana belonging to the Melastomataceae (Myrtales) confirms that the panicle (of flowers or cymes) is the inflorescence which, under the effect of a homogenization process, gives rise to the determinate raceme (a single raceme of flowers or of cymes, or more rarely, a double raceme), and later by truncation, the indeterminate raceme. The impoverishment of these flowering units can give rise to triads which correspond to uninodal racemes morphologically identical with dichasia (triflorous cymes), albeit of a different origin, since the cyme is considered as resulting from the enrichment of a flower and thus assimilated to the latter as a flowering unit. Extreme impoverishment of these uninodal racemes gives rise to a single flower. Melastomataceae have two peculiar features: successively developing pauciflorous groups and long proliferous shoots with short side shoots specifically for flowering. Within the framework of intrafamily classification, all these inflorescences, by virtue of their great diversity and the series of links between their structural variations, may constitute an essential basis for research on phylogenetic links between taxonomic groups.

Reproductive development of common buckwheat (Fagopyrum esculentum Moench) and its wild relatives provides insights into their evolutionary biology

“…Paracladia, which are lateral axes of often more than one order, also terminate in flowering units, but the occurrence of lateral flowering units is not mandatory and may in part depend on environmental conditions. The term ‘flowering unit’ ( Sell and Cremers, 1987 ; Vegetti and Anton, 2000 ; Acosta et al., 2009 ) is an English translation of the original French term ‘unite de floraison’ ( Maresquelle, 1970 ; Sell, 1976 ). Kusnetzova (1988) proposed another translation, ‘floral unit’ (also adopted by Kostina and Yurtseva, 2021 ), which is less appropriate because other authors use the term in different ways (e.g., Tomlinson and Posluszny, 1978 ; Nitao and Zangerl, 1987 ; Claßen-Bockhoff and Bull-Hereñu, 2013 ).…”

The inflorescence in Commelinaceae

“…The typical synflorescence bears a terminal flowering unit, which ends the main axis of the plant, and axillary flowering units, which are found in the apical region of the distal branches (Sell and Cremers, 1987). The flowering unit represents the charac- (B) Synflorescence from the main axis and from the basal branches.…”

Morphological and ontogenetic studies with inflorescences and flowers of Lepidagathis Willd. (Acanthaceae)

“…Sell (1969a) studied particular condensed and ramified inflorescences of many Acanthaceae species, and the presence of accessory structures, especially the accessory flowers and partial inflorescences which constituted the complexity of such flowering shoots. Other families of Lamiales are also known for the common occurrence of accessory buds in the inflorescences (Weber, 2013), as well as on many families amongst the Myrtales (Briggs and Johnson, 1979;Sell and Cremers, 1987;Weberling, 1988), and even on the sister family to all Angiosperms, Amborellaceae (Posluszny and Tomlinson, 2003). These structures are reported to increase the complexity of the inflorescence architecture and the number of displayed flowers by developing into new flowers or branches; and they begin their growth after the associated inflorescence has started its own development (Cavalcanti and Rua, 2008;Naghiloo et al, 2013).…”