Calendula Linnaeus (1753: 921)

Gonçalves, Ana Carla, Castro, Sílvia, Paiva, Jorge, Santos, Conceição & Silveira, Paulo, 2018, Taxonomic revision of the genus Calendula (Asteraceae) in the Iberian Peninsula and the Balearic Islands, Phytotaxa 352 (1), pp. 448-450 : 448-450

Calendula Linnaeus (1753: 921) . Lectotype (designated by Green in Hitchcock & Green 1929: 183): C. officinalis L.

Annual or perennial herbs, sometimes woody at the base, unarmed, with glandular and non-glandular hairs, or, sometimes, white-arachnoid pubescent. Stems prostrate, decumbent, ascending, diffuse or erect, ± branched, leafy, cylindrical, slightly striated, often glandular and aromatic. Basal leaves alternate, undivided—pinnatifid in one taxon in Morocco —mainly in a basal rosette, spatulate, sub-spatulate, obovate, oblanceolate, oblong, lanceolate or linear-oblong, one-nerved, apex acute to obtuse, base attenuate, truncate or auriculate, margins entire, repand-dentate, undulate-dentate or ± irregularly dentate; petiole ± winged; the middle and upper leaves smaller and shortly stalked toward the apex, oblanceolate to lanceolate, usually auriculate, with glandular and non-glandular hairs. Capitula solitary, radiate and heterogamous. Involucre campanulate, with 1–2 rows of bracts, sub-equal, herbaceous, linear-lanceolate, acute, with a narrow hyaline margin, with glandular and non-glandular hairs. Receptacle flat-convex (without palea), glabrous. Ray florets ligulate, female, fertile, usually in 1 row, rarely 2 or more; corolla with a tubular base, hairy (non-glandular) at the base, yellow or orange, with an oblanceolate limb, obtuse, with 3 small teeth in the apex. Disc florets hermaphrodite, functionally male; corolla tubular, 5–lobed, hairy (non-glandular) at the base, yellow, orange, brown or violet-purple. Anthers sagittate, with a caudate base. Style with 2 linear stigmatic branches in ray florets and 2 triangular papillose stigmas in the disc florets. Achenes heteromorphic, ± mucronate; the outer achenes rostrate, straight to sharply curved, with or without dorsal spines, or sometimes bi- or trialate, with entire or toothed wings; the middle achenes usually cymbiform, sometimes bi- or trialate, sub-cymbiform or sub-exalate; the innermost achenes vermiculate, usually smaller, slightly falcate, hook-shaped or almost annulate, transversely rugose-tuberculate on dorsal surface, wingless or with 2 narrow lateral wings. Pappus absent.