that dip temperatures below the freezing point. It grows mostly in the shade of wooded ravines and steep, north-facing slopes under a canopy of other mesic species requiring rich soils, characteristic of the ecological system known as "Southern Coastal Plain Mesic Slope Forest". Canopy tree species thus include Fagus grandifolia, Liriodendron tulipifera, Acer floridanum, Liquidambar styraciflua, Quercus alba, and occasionally pines (Pinus taeda, Pinus glabra). Often these woods are hung with vines (e.g. Smilax spp., Bignonia capreolata). Another rare conifer, Taxus floridana, occasionally grows with Torreya taxifolia. These ravines, known locally as "steepheads", have nearly permanent seeps. The combination of subcanopy shade, a preference for north-facing slopes, and the nearly permanent seeps within the ravines suggest that Torreya taxifolia has already retrenched to the subhabitats within this glacial refugium that offer the coolest conditions during the extremes of summer heat. Because the confined native range of Torreya taxifolia, which includes Torreya State Park, is a well known glacial refugium, the ecological conditions and plants that it associates with there do not provide the full picture of the habitat preferences of this species at this warming time of the Holocene. For this reason, the citizen advocacy group known as Torreya Guardians includes a page on their website titled "Historic Groves of Torreya Trees: Long-Term Experiments in Assisted Migration." "Naturalized groves" is the highest category listed, followed by "mature trees producing seeds" and "mature trees not producing seeds." As of 2022, 14 sites of historic groves are listed, described, mapped, and linked, along with six academic papers that describe the importance of such groves for assessing the viability of assisted migration as climate warms. The northern-most grove of horticulturally planted Torreya taxifolia that produces seeds is in Cleveland, Ohio. Seed dispersal Squirrels are abundant short-distance dispersers of the large seed of Torreya taxifolia today. The 1986 recovery plan (page 3) states that at Maclay Gardens (a horticultural planting in Tallahassee, Florida), "gray squirrels gather the seeds as soon as the arils turn purplish." But larger dispersers may have once carried seeds in their guts and deposited them in feces at longer distances from the parent tree. In her 2001 book, The Ghosts of Evolution, Connie Barlow suggested that T. taxifolia may be an evolutionary anachronism similar to the Osage orange (Maclura pomifera) and Kentucky coffeetree (Gymnocladus dioicus), which are thought to have been dispersed by now-extinct megafauna, such as the mastodon. Barlow