Hornworts are primitive plants growing in damp, humid habitats that lack seeds and vascular tissue. These simple plants exhibit a complex variety of breeding systems, with some species engaging in sexual reproduction and others propagating asexually. The reasons for the evolution of asexuality and its effects on genetic variation in plants are important issues in plant evolution. This project will examine the loss of sexual reproducing in a species of hornwort growing in the Southern Appalachian Mountains. These asexual hornworts were thought to be an endemic species restricted to the Appalachians. But recently other members of the species were found in Costa Rica, and in that locale the species reproduces sexually. Using gene sequence data the researchers will determine the relationships of the Appalachian and Costa Rican hornwort populations and the effect of the loss of sex on genetic variation in natural populations. The work will address broad issues in the evolution of plant sexuality and genetic variation in natural populations.
The research will provide scientific data relevant to the conservation of this unusual hornwort in North America. The graduate student will participate in local biodiversity activities such as BioBlitz, a citizen science activity involving the general public in making a census of species in an area, and he will present public lectures at the Great Smoky Mountain National Park and other venues. The research will support several international collaborative projects with researchers in Central America.
