Flower Structure and Development ofSpondias tuberosaandTapirira guianensis(Spondioideae): Implications for the Evolution of the Unisexual Flowers and Pseudomonomery in Anacardiaceae

Development and Evolution of Unisexual Flowers: A Review

“…Considering that the arrest in development can occur at any step of the developmental sequence of the stamens and carpels (between the initiation of primordia until meiosis completion and production of viable functional gametes; Figure 3; [71]), and by diverse mechanisms [17,73], there are multiple developmental trajectories leading to floral unisexuality associated with the apparent functional convergence (e.g., [74]). Figure 3 illustrates the fact that the development of the organs of the non-functional sex occupies most of the 2D morphospace circumscribed by both axes of the graph.…”

Neotropical Anacardiaceae (cashew family)

“…Both the perianth and/or disk can be absent or severely reduced in wind-pollinated taxa (e.g., Amphipterygium, Orthopterygium, Pistacia), which are found only in Anacardioideae that primarily occur in at least seasonally dry habitats (see below for more information on the disk). The gynoecium is syncarpous (or rarely monomerous) with a superior ovary and as many carpels as there are styles and stigmas or stigmatic lobes (Wannan and Quinn 1991;Endress 2007, 2009;Tölke et al 2021a). The flowers in Neotropical Spondioideae are usually obdiplostemonous with as many carpels as there are petals facing them and usually have an ovary with as many locules as styles and stigmas (Wannan and Quinn 1991;Bachelier and Endress 2009;Tölke et al 2021a).…”

“…The gynoecium is syncarpous (or rarely monomerous) with a superior ovary and as many carpels as there are styles and stigmas or stigmatic lobes (Wannan and Quinn 1991;Endress 2007, 2009;Tölke et al 2021a). The flowers in Neotropical Spondioideae are usually obdiplostemonous with as many carpels as there are petals facing them and usually have an ovary with as many locules as styles and stigmas (Wannan and Quinn 1991;Bachelier and Endress 2009;Tölke et al 2021a). In contrast, in Anacardioideae the androecium is usually haplostemonous (e.g., Astronium, Comocladia, Cotinus, Pseudosmodingium, Rhus), diplostemonous (Lithrea, Mauria, Schinus), or reduced to four stamens (Anacardium excelsum) or a single (Mangifera indica, other Anacardium spp.)…”

“…In some taxa (Anacardium, Mangifera), additional sterile stamens are present. The gynoecium of Anacardioideae is typically trimerous and the ovary pseudomonomerous formed by one carpel with a fertile locule and ovule and two sterile carpels reduced to more or less well-developed styles and stigmas (Wannan and Quinn 1991;Bachelier and Endress 2009;Tölke et al 2021a). However, pseudomonomerous gynoecia have also been reported in Neotropical Spondioideae, in which species usually have carpel dimorphism and reduction in the number of fertile ovules (e.g., some Cyrtocarpa s.l.…”

“…spp., Tapirira). Truly monomerous gynoecia have been reported in both subfamilies (e.g., Campnosperma in Spondioideae, or Anacardium and Mangifera in Anacardioideae) (Wannan and Quinn 1991;Bachelier and Endress 2009;Tölke and Demarco 2020;Tölke et al 2021a).…”