This largely midwestern species appears to have declined much since settlement in Ky., but it is easily overlooked and has been rediscovered in several regions. Without flowering stems, the species is recognizable from its tufts of basal hastate leaves, which are often relatively large (with blades up to 25x 20 cm), yellowish-green (versus generally more bluish in congeners) and have petioles broadly winged along their whole length (versus generally less so). Plants from GRAV (EKY) and adjacent Tenn. (Stewart Co.) have whitish flowers, but those from elsewhere in Ky. have yellowish flowers. N. crepidineus usually grows in rather weedy, thin submesic woods and edges on damp fertile soils near streams, but persistent disturbance from livestock or mowing can eliminate it. Like altissimus, crepidineus can form colonies with new stems arising at ends of 5-10 cm offsets from its rootstocks. But when individual ramets flower they generally die, leading to an appearance of monocarpy (Isaac 2010). Unless exposed to full sun for some of the day, no flowering occurs at all and leaves disappear completely during Jun-Jul; such unusual behaviior is similar to Lilium (with disappearance of leaves in May-Jun). N. crepidineus is a tetraploid (2n = 32), and by far the tallest species in this genus, often reaching 3 m, with local records of 3.65 m in Ohio Co., Indiana (D. Boone, pers. comm.) and 4.04 m in the garden of JC. Rafinesque (1824b; 1836, 4:85) made several colls. of crepidinea from Ky. and elsewhere (PH; see M). He erected the genus Opicrina for these plants, with at least two species, and became quite interested in their properties. He recommended cultivation for medicinal use: "exuding a milk intensely bitter, producing a bitter opium which the name implies... in Central Kentucky rich woods" (for O. latifolia). To date, there has been no published research into the chemistry of N. crepidineus, but sesquiterpene lactones with physiological effects are well known in other Lactuceae (e.g. Shi et al. 2022).