As noted under heterophylla, distinction of that taxon from americana and caroliniana may not be warranted at species level (FNA 6, W). However, deeper analysis is still needed, with examination of potential parallels to the Eurasian complex: widespread T. cordata Mill., mostly central European T. platyphyllos Scop. and mostly Balkan T. tomentosa Moench (Pigott 2012). Included here are the data of Jones (1968), Little (1971 as triangles) and Gm (as open dots). Much of the intermediate material has been previously treated as var. neglecta Spach (or even a species). A few colls. of B were referred to more glabrous forms of T. caroliniana P. Mill., but this was erroneous (Jones 1968, Hardin 1990); they are included here as uncertain records of americana, but probably transitional to heterophylla. The national champion of "Tilia americana" is at the grave of Henry Clay (1777-1852) in the Lexington Cemetery (FAYE): 223 cm dbh, 31 m tall and 26 m wide in 1977 (KDF 2020). Although there is some local belief that this tree dates from well before settlement in the 1770s, it was probably planted during the early 1800s, perhaps even in 1852; average annual diameter growth rates of 1 to 2 cm are documented in other trees of this species across Lexington (Campbell 2013b). Species of Tilia in general are highly sensitive to browsing and burning, but stumps have a strong ability to resprout, potentially conferring great genotypic longevity (e.g. Burns & Honkala 1990, Pigott 2012). Tilia be the only large tree in eastern states with "lignotubers, which develop from suppressed buds at the cotyledonary node of seedlings... On steep slopes, lignotubers can also function as a type of clasping organ that anchors the plant to rocky substrates" (Del Tredici 2001). Species of Tilia are some of the most edible trees for mammals: leaves and cambium can be converted to human food through drying and grinding into flour.