See notes under var. fistulosa. Most colls. of the species from Ky. are clearly referable to var. mollis. There appear to be occasional hybrids with clinopodia or other species, and introgression may have resulted in distinct populations. However, there has been considerable confusion due to difficulties in using or understanding some published keys. The comose "beard" of hairs on the upper petal (lip) is often misinterpreted. In fistulosa these hairs are always distinctly longer at the summit, at least in bud. Other species can have a thin indistinct beard that is not much longer than other hairs on the lip. The strong aromatic properties of fistulosa (as in other species of the genus) involve diverse terpendoids (Zamureenko et al. 1989). Although the smell is pleasant to humans in small doses, repeated exposure to large volumes of living or dried material can become nauseating (J. Seymour, pers. comm.). Plants are generally avoided by mammalian herbivores.