I study the evolution of secondary heterotrophy in photosynthetic organisms, with a particular focus on mycoheterotrophy in orchids (Orchidaceae). Orchids are unique among flowering plants for their lifelong reliance on fungal symbionts, especially during seedling establishment. More than 250 orchid species have entirely lost chlorophyll and depend exclusively on their fungal partners for carbon and nutrients. Many other green orchids display partial mycoheterotrophy, a mixed trophic strategy that combines photosynthesis with fungal-derived carbon acquisition.

To investigate these nutritional pathways, I use stable isotope analysis (δ13C, δ15N, and others) alongside ecological and phylogenetic tools. This work helps clarify the spectrum between autotrophy and full mycoheterotrophy, offering insights into the evolution of plant-fungal mutualisms and the ecological conditions that drive dependency.

Using fungal metabarcoding and environmental sequencing, I investigate the identity and geographic variation of fungal symbionts in temperate North American orchids, particularly the rare three birds orchid, Triphora trianthophoros. This work aims to understand how specificity and flexibility in orchid-fungal partnerships shape species distributions, conservation outcomes, and the potential for symbiotic resilience in changing environments.

As part of broader efforts to study genome degradation in heterotrophic plants, I use molecular phylogenetic approaches to track patterns of gene loss across autotrophic, mixotrophic, and fully mycoheterotrophic lineages. My work focuses on clades such as Vanilloideae (Orchidaceae), where repeated transitions in trophic strategy have left distinctive signatures in the plastid genome. These data help illuminate how shifts in nutritional mode influence plastome evolution and structural decay.

I am also passionate about the diversity and ecology of bryophytes (mosses, liverworts, and hornworts) in North American ecosystems. My research emphasizes documenting hidden diversity through field inventories, specimen vouchering, and public engagement. An ongoing project involves study of the patterns of biogeography in the Coastal Plains bryoflora.

• bcorder@wisc.edu
• brandoncorder95@gmail.com