Sympetalia

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Sympetalie also Gamo- or Monopetalie , refers to the phenomenon that in a angiosperms petals (petals) or corolla tube of a common mount. The corolla tubes are the result of growth processes taking place at different times. The term " intergrowth ", which is often used, is practical, but is not always applicable, as the corolla-tube formation is based on various developmental processes. A distinction is made between late and early sympetaly (terms early and late sympetaly coined by Erbar 1991).

  • Late sympetalism : petals are laid out completely separately from each other and only come into contact later behind the dorsal stamen either through an expansion of the petal bases or through a (sudden) meristem bridge.
  • early sympetalia : petals arise on a "ring wall"; the corolla lobes are formed by increased cell division in mostly 5 places; the stem primordia are later formed in front of the interprimordial "shoulders" of the petals. The corolla tube is formed by continuous growth.

Early and late symptoms can be used as a morphological-ontogenetic feature in the system, especially in the upper evolutionary level of angiosperms. It is characterized by tetracyclic, sympetal flowers with unitegated, tenuinucellate ovules . As far as investigated, early sympetalia is consistently characteristic of the Euasterids II; late sympetalia can be found in many representatives of the Euasterids I.

Early sympathetic families are, for example, Adoxaceae , Dipsacaceae , Asteraceae , Campanulaceae or Araliaceae . Late sympathetic families include Solanaceae , Plantaginaceae , Lamiaceae , and Verbenaceae .

literature

  • C. Erbar: Sympetaly - a systematic character? In: Bot. Jahrb. Syst. 112, 1991, 417-451.
  • P. Leins, C. Erbar: Blossom and Fruit. Morphology, history of development, phylogeny, function, ecology. 2nd edition, Schweizerbart'sche Verlagbuchhandlung, 2008, ISBN 978-3-510-66046-9 .
  • P. Leins, C. Erbar: Flower and Fruit. Morphology, Ontogeny, Phylogeny, Function and Ecology. Schweizerbart Science Publishers, 2010, ISBN 978-3-510-65261-7 .
  • C. Erbar, P. Leins: Synopsis of some important, non-DNA character states in the asterids with special reference to sympetaly. In: Plant Div. Evol. 129, 2011, 93-123.