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