Heracleum mantegazzianum	Heracleum persicum	Heracleum sosnowskyi	Heracleum sphondylium
leaves with biserrate lobes, teeth with concave sides	leaves with broad, short lobes, teeth with more or less convex sides	leaves with broadly ovate or ovate-elongate segments, shape and leaf division variable	leaves with roundes lobes, higher leaves compound
inflorescence more or less flat, with 60 – 120 rays, outer petals of flowers with narrow lobes	inflorescence convex, with 35 – 85 rays, side umbel much smaller than main umbel, outer petals of flowers with broad lobes	inflorescence with 30 – 150 rays,	inflorescence with 15 – 45 rays, stem never reddish
Photo's of H. persicum: Jouko Lehmuskallio; photo 1 of H. sosnowskyi: pl.wikipedia.org, photo 2: wiki-flowers.ru