Development and Structure
Herrera, Maria del Pilar , Bachelier, Julien .
Comparative study of sexual dimorphism in the development of reproductive structures of Orthopterygium, a rare and endemic dioecious genus of Anacardiaceae.
Orthopterygium (A. Gray) Hemsl. is a monotypic and highly endemic genus of the western Andean slopes of Peru. Like its Mexican sister genus, Amphipterygium Schiede ex Standl., it is dioecious and has strongly dimorphic reproductive structures with lax male inflorescences referred to as “catkins”, and unique winged samaroid female inflorescences. Because of their very distinct and unusual female, both genera were first placed in their own family, Julianiaceae, and their systematic affinities were unclear. Historically, they have been compared and related to different families, such as Fagaceae, Juglandaceae, or Anacardiaceae. However, recent chemical and molecular phylogenetic studies confirmed that indeed, Amphipterygium and Orthopterygium were closely related to one another and forming a pair nested in Anacardioideae, the largest of the two subfamilial clade of Anacardiaceae. In addition, a successive comparative and developmental study later showed that the male and female flowers and ovules of A. adstringens shared strong morphological traits with those of Pistacia, but due to a lack of available reproductive material, still little is known about Orthopterygium since its initial description. In this study, we examined the development of flowers and inflorescences of Orthopterygium, and compared them with the reproductive anatomy and morphology of Amphipterygium. Our preliminary results show very little variation between the male structures of the two genera, and both have compact cymose inflorescences that become lax at maturity and hairy flowers with undifferentiated perianth lobes alternating with stamens. The female structures are also essentially similar to those of Amphipterygium, and differ mainly in the number of flowers per cymose inflorescence, and the development of the cupular involucre that surrounds them. Their perianthless female flowers are also essentially similar and have a pseudomonomerous gynoecium with a single syntropous, crassinucellate, and unitegmic ovule with a massive funicle per locule. Both genera thus share many characteristics which are unique or rare elsewhere in Anacardioideae and Anacardiaceae as a whole, and were likely inherited from the common ancestor of Orthopterygium and Amphipterygium.
microMORPH Undergraduate Training Grant Award 2015
1 - Museo de Historia Natural UNMSM, Laboratorio de Sistematica y Diversidad Vegetal, Arenales Avenue 1256, Jesus Maria, Lima, LIMA 14, PERU
2 - SUNY Oswego, Biological Sciences, 30 Centennial Drive, Oswego, NY, 13126, USA
Presentation Type: Oral Paper
Candidate for Awards:Maynard F. Moseley Award