Mapping here is provisional. Var. comosa was initially described as A. pitcheri Torr. & Gray, and its status remains uncertain. It tends to occur on more damp or fertile soils than typical bracteata, and to flower a few weeks earlier. Previous authors (D, F) reported that comosa differs in its generally more hairy surfaces, larger leaves, larger flowers with deeper purple color (versus lilac to white), and larger seeds; D. Boone (pers. comm.) has noted distinctly earlier flowering in s. Ohio. Recent research (Parker 1996, Callahan 1997; see also W) has indicated that the most useful diagnostic differences may be in its fully grown leaves: longer petioles (ca. 6-10 cm versus 3.5-5.5 cm), longer petiolules of terminal leaflets (ca. 1.5-2 mm versus 1-1.5 mm), and longer terminal leaflets (ca. 5.5-9 cm versus 3-5.5 cm). Parker et al. (2004; plus cited work) have shown that distinct genotypes of rhizobial bacteria are associated with different lineages of Amphicarpaea.