Floral visitors of a Colorado endemic chasmophyte, Telesonix jamesii (Saxifragaceae)

Telesonix jamesii, a rare and imperiled species of perennial saxifrage, is restricted to rocky habitats at high elevations across 21 isolated, known populations in the southern Rocky Mountains of Colorado and New Mexico. Despite its imperiled conservation status, very little is known about the natural history of T. jamesii. We studied pollination of this species during the summers of 2019-2021 at multiple locations on Pikes Peak, Colorado. We conducted a total of 899 min of pollinator surveys, identifying all floral visitors during this time period. We then examined floral visitors for the presence of T. jamesii pollen to determine which species might be effective pollinators. We found that flowers of T. jamesii are visited by a diverse assemblage of insects and one species of hummingbird. Bumble bees (Bombus) were the most commonly observed species visiting flowers, as well as the only group found carrying T. jamesii pollen on their bodies. Our findings suggest that T. jamesii is infrequently pollinated, and we speculate that gene flow for this species may be low. This work constitutes the first investigation into the field pollination ecology of T. jamesii. Our study warrants future investigation into the population genetics of this species as well as surveys of historical occurrences and high-suitability habitat for populations.