Calendula arvensis Linnaeus (1763: 1303)

Gonçalves, Ana Carla, Ouhammoud, Ahmed, Amirouche, Rachid, Santos, Conceição, Figueiredo, Estrela & Silveira, Paulo, 2023, A taxonomic revision of Calendula (Asteraceae) in Morocco, including some taxa from Algeria and Tunisia, Phytotaxa 605 (1), pp. 1-83 : 26

publication ID	https://doi.org/ 10.11646/phytotaxa.605.1.1
persistent identifier	https://treatment.plazi.org/id/E82AFC0A-1557-CA76-66ED-FF588210FBE0
treatment provided by	Plazi
scientific name	Calendula arvensis Linnaeus (1763: 1303)
status

Treatment

1. Calendula arvensis Linnaeus (1763: 1303) View in CoL View at ENA ; Desfontaines (1799: 306); Battandier (1888: 478); Bonnet & Barrette (1896: 509); Pitard (1913: 58); Pampanini (1931: 452); Jahandiez & Maire (1934: 788); Quézel & Santa (1963: 967); Heyn et al. (1974: 180); Meikle (1976: 206); Jeffrey (1979: 326); Pottier-Alapetite (1981: 1022); Alavi (1983: 193); Valdés et al. (1987: 78); Valdés et al. (2002: 671); Boulos (2002: 266); Ibn Tattou & Fennane (2009: 27); Dobignard & Chatelain (2011: 185); Gonçalves et al. (2014: 270). Type:—EUROPE. ‘In Europae arvis’, L̂fling s.n. in Herb. Linnaeus 1035.1 (lectotype LINN!, designated by Heyn et al. (1974: 182)).

Description:––Annual herbs. Stems (2) 17.3–45.5 (80) cm long, ascending to erect, sometimes decumbent, branched at the base, with glandular and non-glandular hairs, in varying proportions, ± viscous. Basal leaves (1.2) 2.4–4.8 (6.5) × (0.2) 0.4–0.8 (1.1) cm, (0.3) 0.3–0.5 (0.5) mm thick, oblanceolate, acute or obtuse, margin sub-entire to sinuate-dentate, base attenuated in a petiole, with glandular and non-glandular hairs; the middle and upper cauline leaves progressively smaller towards the apex, oblanceolate to lanceolate, sessile, usually auriculate. Capitula solitary, (1) 1.2–1.4 (2) cm in diameter. Outer achenes rostrate (5) 7.1–11.7 (15.2) × (0.8) 1.3–1.9 (2.7) mm, usually strongly curved and with long spines at the back, usually with two small teeth, one at the base and another at the apex, sometimes bialate (8.3) 10.8–12.4 (13.3) × (7.2) 7.7–9.3 (10.2) mm, with two wings, with irregularly incise margins, extended along both sides up to the apex; middle achenes cymbiform (4.8) 6.7–8 (8.5) × (3.8) 5.3–7 (8) mm, sometimes lacking; inner achenes vermicular-alate (3.5) 3.8–5.2 (5.8) × (2) 2.7–3.3 (3.7) mm, hook-shaped to circular, with two narrow lateral wings, and/or vermicular-exalate (3.2) 3.7–4.5 (5.3) × (1.2) 1.2–1.7 (1.8) mm, circular. Figures 18 View FIGURE 18 and 31E View FIGURE 31 .

Habitat and distribution:—Widespread throughout the North Africa ( Morocco, Algeria, Tunisia, Lybia, Egypt) on waste grounds, cultivated fields and grasslands or on the margin of roads and ditches, up to elevations of 1300 m. Also native in Central and South Europe, SW Asia and Macaronesia. Introduced in other parts of the globe such as Australia and California. Figure 15 View FIGURE 15 .

Conservation status:—Least Concern (LC). This is a widespread species in the study area, and in the circum- Mediterranean region, including Central Europe and the Middle East. It inhabits ruderal and waste grounds and faces no major threat.

Chromosome number:— 2n = 44.

Genome size:—5.23 ± 0.29 pg.