Changing views of flower evolution and new questions

Heterostyly accelerates diversification via reduced extinction in primroses

“…Our results illustrate the complexity of possible diversification trajectories across heterostylous angiosperms, with both early gains and later losses of heterostyly prompting increased net diversification. Heterostyly is one of many floral innovations that were repeatedly gained and lost in angiosperms [16,17]. Many such innovations, and especially those affecting reproductive ecology and mating systems, are likely to have had similarly complex effects on patterns of species diversification [26].…”

“…One overarching hypothesis proposed to explain the evolutionary success of angiosperms posits that they have inherently higher phenotypic evolvability than other land plants, allowing them to 'reinvent themselves' time and again ( [10], p. 377). The idea of evolutionary reinvention is epitomized by the spectacular diversity of flowers and inflorescences, their associated pollination syndromes and sexual systems and the prevalence of parallel and convergent evolution of similar floral features [16,17].…”

The ontogenetic bases for variation in ovary position in Melastomataceae

“…Contrary to what was accepted in the past, the reconstruction of the ancestral state for ovary position presents a very dynamic picture between the angiosperms, both phylogenetically and ontogenetically (Gustafsson and Albert, 1999; Soltis et al, 2003; Endress, 2011). The data presented here on floral development insert Melastomataceae among families with ontogenetic characteristics that are labile enough to sustain multiple events of transformation in the ovary position.…”

“…The data presented here on floral development insert Melastomataceae among families with ontogenetic characteristics that are labile enough to sustain multiple events of transformation in the ovary position. Among these families, we highlight those taxa that exhibit a superior ovary derived from taxa with an inferior ovary (Soltis et al, 2003; Endress, 2011), such as Araliaceae (Eyde and Tseng, 1969; Costello and Motley, 2004), Asphodelaceae (Rudall, 2002), Begoniaceae (Charpentier et al, 1989), Bromeliaceae (Sajo et al, 2004), Campanulaceae (Kaplan, 1967), Haemodoraceae (Simpson, 1998), Rhamnaceae (Medan, 1988; Richardson et al, 2000), Rhizophoraceae (Juncosa, 1988), Rubiaceae (Igersheim et al, 1994; Groeninckx et al, 2007; Vrijdaghs et al, 2015), Saxifragaceae (Kuzoff et al, 2001; Soltis and Hufford, 2002), and Vochysiaceae (Litt and Stevenson, 2003).…”

“…We thus assume that the ontogenetic analysis of the variation of ovary position in Melastomataceae is interesting for several reasons: (1) variations of these traits are unusual within the same family, since this character is relatively stable among angiosperms (Endress, 2010, 2011); (2) the monophyletic status of Melastomataceae (Clausing and Renner, 2001) allows comparisons between structures that share the same evolutionary history; and (3) a group with such variations is also a model for testing the predictive validity for the correlation between the floral apex shape and the position occupied by the ovary in the anthetic flower (sensu Soltis et al, 2003). Thus, the objective of this study was to determine which changes of the floral meristem explain the variation in the position of the ovary in perigynous and epigynous flowers of six Melastomataceae species.…”