Stems
usually hollow; leaves simple or compound; petioles often dilated at the base;
flowers small in umbels, rarely heads; umbels often with bracts (the involucre);
in compound umbels, the secondary rays often subtended by secondary bracts (the
involucels); base of style (stylopodium) often expanded; fruit of 2 seed-like
dry carpels with contiguous inner surfaces (the commissure), each carpel with
lengthwise ribs, usually 5 and sometimes with 4 smaller ones, in the intervals
between the ribs oil tubes are commonly found; carpels oftne separating from
each other, supported on the summit of a slender axis (the carpophore).
It is very helpful to have the mature fruit when identifying the species.
Heracleum maximum (Heracleum lanatum)
Osmorhiza berteroi (Osmorhiza chilensis)