Calendula L.
Annual or perennial herbs, sometimes woody at base, not armed. Lvs alternate, simple, entire or toothed. Capitula solitary or in loose corymbs. Involucral bracts in 1-2 rows, with membranous margins. Receptacle flat; scales 0. Outer florets ♀, ligulate; ligules yellow or orange. Inner florets tubular, with innermost functionally ♂ (some disc florets transformed into ligulate florets in cvs). Achenes heteromorphic, incurved, ridged, tuberculate or spiny on back; outer achenes narrowly beaked, or not beaked and 2-3-winged; inner achenes curled in ± 1 complete turn, usually without well-formed beaks or wings.
Key
c. 20 spp., Macaronesia, S. Europe, Mediterranean, E. to Caucasia, Iran and Afghanistan. Naturalised spp. 2.
The striking heteromorphic achenes distinguish Calendula spp. from all other Asteraceae in N.Z.
