Cosmos atrosanguineus

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Cosmos atrosanguineus
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Heliantheae
Genus: Cosmos
Species: C. atrosanguineus
Binomial name
Cosmos atrosanguineus
(Hook.) Voss 1894, not Stapf 1929[1]

Cosmos atrosanguineus (Chocolate Cosmos) is a species of Cosmos, native to Mexico, where it is extinct in the wild. The species was introduced into cultivation in 1902, where it survives as a single clone reproduced by vegetative propagation.[4]

Cosmos atrosanguineus is a herbaceous perennial plant growing to 40–60 cm tall, with a fleshy tuberous root. The leaves are 7–15 cm long, pinnate, with leaflets 2–5 cm long. The flowers are produced in a capitulum 3-4.5 cm diameter, dark red to maroon-dark brown, with a ring of six to ten (usually eight) broad ray florets and a center of disc florets; they have a light vanillin fragrance (like many chocolates), which becomes more noticeable as the summer day wears on.[5]

Cultivation and uses[edit]

The single surviving clone is a popular ornamental plant, grown for its rich dark red-brown flowers. It is not self-fertile, so no viable seeds are produced, and the plant has to be propagated by division of the tubers, or by tissue culture.[6]

It requires partial sun or full sun, and flowers from mid to late summer. It is frost-sensitive (Zones 6-11); in temperate zones, the tuber has to be dug up and stored in a frost-free store over the winter.


  1. ^ The International Plant Names Index
  2. ^ Tropicos
  3. ^ The Plant List
  4. ^ Encyclopedia of Life
  5. ^ [1]
  6. ^ Huxley, A. (ed.) 1992. New RHS Dictionary of Gardening 1: 739. Macmillan.