Compilation
Arctotheca calendula

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Name

Identification
Arctotheca calendula (L.) Levyns [family ASTERACEAE ]
Related name
  • Arctotheca calendula

Flora

Entry for Arctotheca calendula (Linnaeus) Levyns [family COMPOSITAE]
Herbarium
Flora of North America (FNA)
Collection
Flora of North America
Resource Type
Reference Sources
Entry From
Flora of North America, Vol 19,
Names
Arctotheca calendula (Linnaeus) Levyns [family COMPOSITAE], J. S. African Bot., 8: 284. 1942
Arctotis calendula Linnaeus [family COMPOSITAE], Sp. Pl., 2: 922. 1753
Cryptostemma calendula (Linnaeus) Druce [family COMPOSITAE]
Treatment Author(s)
Alison McKenzie Mahoney
Information
Plants usually stoloniferous. Leaves obovate, (2–)5–20(–30+) × (1–)2–5(–7) cm, margins pinnati-sect (lyrate to runcinate), remotely prickly, abaxial faces white-pannose, adaxial faces sparsely puberulent to arachnose, usually glandular as well. Heads 4–7 cm diam. (across the rays). Phyllaries: outer reflexed, apices mucronate, white-woolly; inner appressed, margins hyaline, apices rounded, glabrous. Ray florets 11–17(–25); corolla laminae abaxially greenish to purplish, adaxially yellow (drying to basally ochroleucous, apically blue, forming bull’s eye around disc), 10–25 × 2–4 mm, sparsely puberulent, glandular. Disc florets: corollas yellow proximally, bluish distally. Cypselae dark brown, 3 mm, densely woolly; pappi ca. 0.5 mm (usually hidden by hairs on cypselae).
Phenology
dec-feb (winter), mar-may (spring), jun-aug (summer), oct-nov (fall)
Altitude range
0–300 m;
Distribution
Africa.USA Calif.
Discussion
Most populations of Arctotheca calendula are sterile and spread aggressively by stolons; at least three populations in the flora are fertile and highly invasive. The species is listed by the California Exotic Pest Plant Council (CalEPPC) as a weed with the potential to spread explosively (Red Alert, CDFA A).
Native/Introduced
introduced;

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