Taxonomic revision of the genus Calendula (Asteraceae) in the Canary Islands Author Simão, Inês Departamento de Biologia e CESAM, Universidade de Aveiro, 3810 - 193, Aveiro, Portugal. Author Reyes-Betancort, J. Alfredo Jardín de Aclimatación de la Orotava (ICIA), C. Retama, 2, 38400 Puerto de la Cruz, Santa Cruz de Tenerife, Spain. Author Talhinhas, Pedro LEAF- Linking Landscape, Environment, Agriculture and Food, Associate Laboratory Terra, Instituto Superior de Agronomia, University of Lisbon, Tapada da Ajuda, Lisboa, Portugal. Author Morais-Cecílio, Leonor LEAF- Linking Landscape, Environment, Agriculture and Food, Associate Laboratory Terra, Instituto Superior de Agronomia, University of Lisbon, Tapada da Ajuda, Lisboa, Portugal. Author Silveira, Paulo Departamento de Biologia e CESAM, Universidade de Aveiro, 3810 - 193, Aveiro, Portugal. text Phytotaxa 2024 2024-03-11 640 2 125 160 http://dx.doi.org/10.11646/phytotaxa.640.2.3 journal article 10.11646/phytotaxa.640.2.3 1179-3163 13213550 3. Calendula ricardoi I.Simão, Reyes-Bet. & P.Silveira , sp. nov. Holotype :— CANARY ISLANDS . Fuerteventura : Road from Betancuria to Pájara , 30 March 1975 , P. L. Perez & J. R. Acebes 4802 (TFC! 4802). Diagnosis :—This species is distinguishable from C. tripterocarpa by the well-developed rostrate achenes, usually with a long rostrum, and the larger size of the plants and leaves, and also by the flowering capitula with purple/reddish spots under the ligules. It is distinguishable from C. arvensis by the trialate achenes with entire to sub-entire lateral wings. Description :—Annual herbs. Stems (32) 33–42 (50) cm long, occasionally longer, erect, branched at the base, with dispersed glandular and non-glandular hairs. Basal leaves usually (4.1) 4.9–6.9 (7.6) × (0.5) 0.95–1.3 (1.6) cm, (0.2) 0.3–0.4 (0.5) mm thick, ovate to oblong, less frequently oblanceolate, acute, margins entire to sub-entire, sometimes dentate, higher leaves similar to the basal ones but smaller, sessile, auriculate, possessing both glandular and non-glandular hairs. Capitula concolorous, (1.4) 1.7–2.7 (3) cm in diameter, solitary. Involucre (5.3) 6.1–8.1 (8.5) mm long, bracts in 1–2 rows, lanceolate, acute, green with a defined purple apex, glandular pubescent. Ray florets 13–21, (8.1) 9.6–14.9 (16.7) × (1) 1.9–2.3 (2.5) mm, arranged in one row, yellow or orange, sometimes with purple spots, tri-lobed. Disc florets 39–50, (2.5) 2.7–2.9 (3.7) × (0.6) 0.8–1 (1.2) mm, five-lobed, yellow to orange. Anthers 1.4–1.5 mm long, styles 1.9–2.3 mm , bifid. Achenes rostrate (10.4) 13.7–22 (25) × (1.8) 2.6–3.6 (5.1) mm, most of the times forming a ± 90º angle, sometimes only slightly curved, with a long rostrum and poorly developed dorsal spines, and one to two ventral teeth, one at the base or one at the apex, many times both; achenes trialate, (8) 8.6–10.5 (11.5) × (7.1) 8.1–9.5 (11.1) mm, lateral and ventral wings sub-entire, rarely dentate, flat in the back; achenes cymbiform (4.6) 5.1–6.1 (7) × (2.8) 3.5–4 (4.4) mm, strongly curved without ventral or dorsal wings but with ventral teeth, sometimes muricate in the back; achenes vermiform-alate (3.7) 3.9–4.5 (6) × (1.9) 2.3–2.7 (3.2) mm, circular to hook-shaped, with two lateral wings and ventral teeth; vermiform-exalate (3) 3.4–3.7 (5.1) × (1.1) 1.2–1.3 (1.5) mm. Habitat and Distribution :—Limited to the central-western part of Fuerteventura, between Betancuria and Pájara, growing along the margins being part of ruderal nitrophilous and subnitrophilous weed communities. These annual communities are found in a degraded landscape characterized by shrubby Chenopodiaceae species or by betterpreserved shrub communities dominated by succulent Euphorbia species. Elevation :— 250– 400 m . Illustrations :— Figures 8 , 10D and 11C . Conservation status :—Vulnerable (VU). Chromosome number :— 2n =54. Genome size :—5.1 pg ± 0.7. Etymology :—Named after Spanish botanist Ricardo Mesa Coello (b. 1954), who worked on the monitoring of the endangered flora of the Canary Islands , contributing to its conservation and better knowledge.