Abstract
Fenerivia species (Annonaceae) are characterized by a prominent flange immediately below the perianth, which has been interpreted as synapomorphic for the genus. The homology of this flange is controversial: previous studies of Fenerivia heteropetala (an aberrant species, with 12 perianth parts in three whorls) have suggested that the flange may represent a vestigial calyx resulting from a disruption to the homeotic control of organ identity during floral development. Comparative data on floral vasculature in Fenerivia capuronii are presented to elucidate the homology of the flange in other Fenerivia species (which possess nine perianth parts in three whorls, typical of most Annonaceae). The flange in F. capuronii differs from that in F. heteropetala as it is unvascularized. It is nevertheless suggested that the flange is likely to be homologous, and that a homeotic mutation in the F. heteropetala lineage resulted in the formation of a vestigial but vascularized calyx that fused with the otherwise unvascularized flange.
Highlights
The Annonaceae is one of the most species-rich families of early-divergent angiosperms, with 2,292 species recognized in 108 genera [1]
Several studies [4,5,6,7,8,9] have demonstrated that most Annonaceae flowers possess a consistent vascular anatomy, comprising a perianth cortical vascular system (CVS, sensu Deroin [6,10]) in which the sepals are supplied by three basal traces and the petals each generally possess a single basal trace: the vascular traces supplying the outer petal whorl are basally fused with the two lateral traces feeding adjacent sepals, whereas the vascular traces supplying the inner petal whorl are basally fused with the median sepal traces
The inner perianth parts are supplied by vascular bundles from the same source as the median bundles of the opposing outer perianth whorl (b in Figures 4A, 4C, 4F, 5)
Summary
The Annonaceae is one of the most species-rich families of early-divergent angiosperms, with 2,292 species recognized in 108 genera [1]. Despite this considerable taxonomic diversity, most species are uniform in their underlying floral structure: the flowers are typically hermaphroditic and protogynous, with a tripartite perianth consisting of a whorl of three sepals and two whorls of three petals that are generally morphologically distinct. Study of floral vascular anatomy provides a wealth of structural information that is invaluable in interpreting evolutionary changes, including the consequences of putative homeotic mutations. Several studies [4,5,6,7,8,9] have demonstrated that most Annonaceae flowers possess a consistent vascular anatomy, comprising a perianth cortical vascular system (CVS, sensu Deroin [6,10]) in which the sepals are supplied by three basal traces (one median and two lateral traces) and the petals each generally possess a single basal trace: the vascular traces supplying the outer petal whorl are basally fused with the two lateral traces feeding adjacent sepals, whereas the vascular traces supplying the inner petal whorl are basally fused with the median sepal traces
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
