Merremia

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Merremia
Merremia hederacea

Merremia hederacea

Systematics
Nuclear eudicotyledons
Asterids
Euasterids I
Order : Nightshade (Solanales)
Family : Bindweed family (Convolvulaceae)
Genre : Merremia
Scientific name
Merremia
Dennst. ex Endl.

Merremia is a plant genus in the family of wind plants (Convolvulaceae). The only 54 species left since 2017 are distributed from the tropics to the subtropics of America, Africa and Asia and occur in Asia even in the temperate areas.

description

Merremia species are hairy or hairless climbing plants that usually grow herbaceous . The leaves are entire, lobed or fingered with three to seven partial leaves or assembled in a foot-shaped manner.

The flowers stand individually in the leaf axils or in little-flowered cymes on long stalks. The inflorescences are accompanied by small bracts , these are linear or lanceolate.

The hermaphrodite flowers are radially symmetrical with a double flower envelope . The sepals are almost equally long and elongated or elliptical in shape. The crown is bell-shaped and colored white, yellow or purple; occasionally it is slightly lobed. The stamens and pistil do not protrude beyond the crown. The stamens can be equally long or slightly different in length. The dust bags are usually twisted after opening. The pollen grains are smooth. The ovary is mostly hairless, consists of two or three carpels with four to six ovules . The stylus is thread-like, the stigma is spherical or two-spherical.

The capsule fruits are thin-walled and are surrounded by the enlarging calyx. They jump up in four chambers or irregularly. They contain four to six seeds , rarely fewer or only one. The seeds are hairless or hairy.

The number of chromosomes is usually 2n = 30, less often 32 or 58.

Merremia hederacea
Merremia hirta
Merremia palmata

Systematics and distribution

The genus Merremia was established in 1841 by August Wilhelm Dennstedt in Stephan Ladislaus Endlicher : Genera Plantarum (Suppl. 1) 18, p. 1403. The generic name Merremia honors the German natural scientist Blasius Merrem (1761-1824). Synonyms for Merremia Dennst. ex Endl. nom. cons. are: Merremia Dennst. (Published invalid in 1818), Spiranthera Bojer ex Desjardins nom. illegal. Skinneria Choisy . Since 2017, ARSimões & George William Staples have added numerous species to the genus Distimake Raf. or Carmonea Raf. posed.

The genus is classified within the Convolvulaceae in the tribe Merremieae, which has been set up with reservations.

The distribution area of ​​the approximately 54 species includes the tropics and subtropics of America, Africa and Asia and in Asia also extends into the temperate areas.

Here is a selection of the types:

  • Merremia hederacea (Burm.f.) Hallier f. : It occurs from the tropics and subtropics of the Old World to the islands in the Pacific.
  • Merremia hirta (L.) Merr. : It occurs from tropical and subtropical Asia to Queensland.
  • Merremia palmata Hallier f. : It occurs in tropical and southern Africa and in India.
  • Merremia sibirica (L.) Hallier f. : It occurs from southern Siberia to the western Himalayas and to Far Eastern Asiatic Russia.
  • Merremia yunnanensis (Courchet & Gagnep.) RCFang : It occurs in three varieties in the Chinese provinces of Sichuan, Yunnan and Guizhou:
    • Merremia yunnanensis var. Glabrescens (CYWu) RCFang : It occurs in Yunnan.
    • Merremia yunnanensis var. Pallescens (CYWu) RCFang : It occurs in Sichuan and Yunnan.
    • Merremia yunnanensis var. Yunnanensis : It comes in the Chinese provinces of Sichuan, Yunnan and Guizhou steps:

This genus has not been included in this category since 2017:

swell

literature

  • Henri Alain Liogier: Descriptive Flora of Puerto Rico and Adjancent Islands, Spermatophyta , Volume IV: Melastomataceae to Lentibulariaceae. Universidad de Puerto Rico, 1995, ISBN 0-8477-2337-2 .

Individual evidence

  1. ↑ a b c d e f g h i j k l m Rafaël Govaerts (Ed.): Merremia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 24, 2018.
  2. ↑ Merremia at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
  3. ↑ Merremia at Tropicos.org. Missouri Botanical Garden, St. Louis, Retrieved November 28, 2017.
  4. ↑ Helmut Genaust: Etymological dictionary of botanical plant names. Birkhäuser, Basel / Stuttgart 1976, ISBN 3-7643-0755-2 .
  5. ^ Saša Stefanović, Daniel Austin and Robert Olmstead: Classification of Convolvulaceae: A Phylogenetic Approach. In: Systematic Botany , Volume 28, Number 4, 2003, pp. 791-806. doi : 10.1043 / 02-45.1 (currently unavailable) ( online )

Web links

Commons : Merremia  - collection of images, videos and audio files