#dioecy

Sex-specific functional traits in cycads

Poor man’s cycad. Wikipedia Commons, licensed under the Creative Commons Attribution-Share Alike2.0 Generic license. The Mesozoic is often referred to as the “age of cycads”. During this period, dinosaurs roamed vast cycad forests, yet modern cycads are a vestige of their Mesozoic glory. Extant species represent the oldest lineage of dioecious seed-bearing plants. This curious phylogenic position…

Amborella trichopoda helps reveal features of the first flowering plants

The flowering plants, or angiosperms, are the largest group of plants, containing over 300 000 living species.  All these species descend from a single, most recent common ancestor (MRCA), which probably lived some 225 to 140 million years ago. Its exact date is still rather uncertain!  Unfortunately, we don’t have a fossil of the MRCA of the living angiosperms, and even if we did, without a…

Genetic sex determination and sexual instability in Amborella trichopoda

Amborella trichopoda, the sister species of all other extant angiosperms, is typically dioecious, producing male and female flowers on separate individuals. Anger et al. map sex phenotypes onto a phylogeny of basally diverging angiosperms using maximum parsimony. Sex-ratios and phenotypes were studied in parallel over two consecutive flowering seasons for an ex situ population of A. trichopoda.…