Arnold Arboretum and Department of Organismic and Evolutionary Biology
Much of my research has been devoted to an investigation of the origin and early evolution of flowering plants (Darwin's abominable mystery). These efforts have focused on the evolution of double fertilization and endosperm, two of the most important and defining features of flowering plants.
Our analyses of the origin of the angiosperm reproductive syndrome have drawn upon a variety of approaches from cell biology to developmental biology to the integration of inclusive fitness theory. Recently, we discovered that most basal angiosperms appear to produce a diploid endosperm, thus reversing a century of thought on the presumed genetics and ploidy of endosperm in the earliest flowering plants (Friedman and Floyd 2001; Williams and Friedman 2002). We have also closely examined (Floyd and Friedman 2000, 2001) evolutionary developmental transitions between cellular and syncytial endosperms.
Developmental pattern and process associated with the evolution of ontogenies in plants continues to be a major focus of the lab. These studies are focused on documenting and understanding developmental variation among the determinate haploid gamete-producing generations of plants, the male and female gametophytes. This work has provided new insights into the modifications of development, both heterochronic and non-heterochronic, which underlie the origin of novel reproductive patterns in diverse lineages of plants (Friedman and Carmichael 1998; Friedman 1999, 2001). Most recently, we have begun to examine the evolution of modularity in female gametophytes of flowering plants (Williams and Friedman ms in prep).
My students and I also have a strong interest in the first major radiation of photosynthetic life on land, that of the vascular plants. This program of study has produced an explicit developmental model for the evolutionary origin of water conducting cells in land plants (Friedman and Cook 2000). An associated project (currently funded by the NASA Astrobiology Program) is underway to examine the evolution of multicellularity and symbiosis (mycorrhizal associations) during the early evolution of land plants. This research is highly interdisciplinary, working at the interfaces of paleobotany, molecular systematics, plant anatomy and life cycle ecology.