Comparative floral structure and evolution in Galipeinae (Galipeeae: Rutaceae) and its implications at different systematic levels

Abstract

Galipeinae (Rutoideae) is the most species-rich subtribe of Rutaceae in the Neotropics. The taxonomy of Galipeinae is complex as molecular phylogenies demonstrate that rearrangements of genera are necessary to reach the monophyly of the subtribe. A few detailed studies have found variability in floral features, such as different patterns of organ fusion and symmetry, with potential systematic importance. However, this was shown for a limited number of taxa. This study aimed to provide a broader comparative account of the floral structure of Galipeinae and closely related taxa of Rutoideae. Some floral features, such as the cochlear aestivation of petals and a free zone of carpels, support the monophyly of Galipeinae without Adiscanthus. Other features, such as apocarpy, anacrostyly, antitropous ovules and zig-zag micropyles, also provide support for the affinity of Rutaceae in Sapindales. Furthermore, complex patterns of organ synorganization of Galipeinae are more diverse than previously shown, and are probably correlated to other features that are not found elsewhere in Sapindales. Finally, we identified homoplastic features that are also widespread in asterids, probably related to similar floral functions, such as variable patterns of monosymmetric tubular corollas, two fertile adaxial stamens with basal appendages of variable length and herkogamy.

A new subfamily classification of the Citrus family (Rutaceae) based on six nuclear and plastid markers

“…Even in taxa (e.g., Rauia Nees & Mart.) with an actinomorphic corolla, the flower as a whole is zygomorphic because of the androecium (El Ottra & al., 2019).…”

Evolution of reproductive traits in the mahagony family (Meliaceae)

“…7D). Gynophores also occur in Simaroubaceae, several Rutaceae (e.g., El Ottra et al, 2013, 2019), and Sapindaceae (e.g., Beck, 2004).…”

“…Finally, detailed data from floral morphological analyses may be very helpful in these evolutionary issues among the Meliaceae. In other families of Sapindales studies have been done in a comparative context and mostly contributed to the systematics of the groups (e.g., Bachelier & Endress, 2008, 2009; Pirani et al, 2010; Bachelier et al, 2011; El Ottra et al, 2013, 2019; Alves et al, 2017). Thus, this moment is conducive to a study with flowers of Meliaceae, in a comparative context, aiming to provide subsidies to the macrosystematics and macroevolution of the family.…”

Mechanical Forces in Floral Development

“…This can be observed in buds of Rutaceae, where space availability is restricted at the moment of nectary growth, which occurs usually late in floral development [103]. Such "imprint" in the outline of the annular intrastaminal nectaries can be observed in some Galipeinae of Rutaceae, mostly due to the pressing of filaments and petals in its outer side, and to carpels in its inner side (Figure 11A,B; See also Figures 1D and 3G in [104] and Figures 6I, 16G1 and 16H1 in [105]). Similarly, in Arctostaphylos pungens Kunth (Ericaceae), this is also clear in the basal protuberances of the nectary, formed only between stamen filaments, where more space is available (Figure 11C,D).…”