More collections are needed to document this enigmatic globally imperiled species, which appears to have been widely scattered in the Ohio Valley (W.Va., Ohio, Ind., Ky.) before settlement, with some western extensions into Mo. and edges of the Great Plains (Brooks & Freeman 1989). Plants have been found in at least 100-200 disjunct localities across its range since 1984, but mostly in small and somewhat ephemeral patches. In Ky. it appears to have been formerly common in browsed upland woods of the Bluegrass region (with no evidence of fire), as well as browsed alluvial terraces. Some uncertain records mapped here are just historical references or sight records. It now survives mostly in mowed woods (old yards or parks), along old trail margins, and at associated streambank crossings. T. stoloniferum is the only species of the genus not known to have rhizobial nodules that fix nitrogen (Morris et al. 2002). It is dependant on the right combination of seasonally damp fertile soil, partial shade, and frequent disturbance of vegetation with bared soil (Campbell et al. 1989, Burkhart et al. 2013). Despite federal listing as an "Endangered Species" since 1985, no populations appear to have come under truly stabilizing naturalistic management, and there is continued reticence by conservationist agencies to use ungulates in management. The robust stolons of stoloniferum are usually distinctive, ca. 2-3 mm thick (versus 1-2 mm in repens), often up to 0.3-0.8 m long in good conditions, and mostly produced after flowering during Jun-Jul. Leaves lack any 'chevron' marks, as often found in repens and reflexum. The most distinctive character is the thick erect peduncle and its pair of subtending subopposite leaves with unusually short petioles (ca. 1-3 cm). Calyx lobes are ca. 2-3 mm long. Flowers appear in late Apr to mid-May.