e-Key v<span id="jodit_selection_marker_1706003301669_24942220974300566" data-jodit_selection_marker="start" style="line-height: 0; display: none;"></span>3 - *Amb<span id="jodit_selection_marker_1706003301669_6168751416177249" data-jodit_selection_marker="end" style="line-height: 0; display: none;"></span>rosia
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Interactive keys to the identification of seed plants of southern Africa using keys based on plant morphology.

Asteraceae - Heliantheae - *Ambrosia L.

Description:

  • Annual or perennial herbs, sometimes shrubby, monoecious
  • Leaves usually alternate, petiolate, simple, lobed or pinnately dissected, margins entire
  • Capitula unisexual
  • Male capitula in leafless spikes or racemes, usually drooping, hyaline, many-flowered
  • Involucre cup-shaped; bracts connate
  • Receptacle with filiform paleae or epaleate
  • Corolla tubular, campanulate above, 5-lobed
  • Anthers ± free, with incurved, linear apical appendage, base entire
  • Style undivided, truncate, penicillate
  • Ovary abortive
  • Female capitula sessile, solitary or clustered in upper leaf axils below males, 1-flowered
  • Involucre enveloping cypsela and becoming indurated, turbinate, with 4-6 spines on shoulder below neck through which long, linear, papillose style branches exserted
  • Corolla 0
  • Cypselas ovoid, smooth
  • Pappus 0
  • x = 9 (8) (aneuploids, high polyploidy)

Nomenclature:

  • *Ambrosia L.
    • Linnaeus: 987 (1753)
    • Linnaeus: 425 (1754)
    • Oliver & Hiern: 370 (1877)
    • Phillips: 813 (1951)
    • Wild: 2 (1967)
    • Hilliard: 295 (1977)
    • Karis & Ryding: 621 (1994)

Distribution & Notes:

  • Global: Species 43, North and South America
  • Southern Africa: Species 3, naturalised, known from North-West, Gauteng, Mpumalanga, Free State, KwaZulu-Natal, Lesotho, Eastern Cape

References:

  • HILLIARD, O.M. 1977. Compositae in Natal. University of Natal Press, Pietermaritzburg
  • KARIS, P.O. & RYDING, O. 1994. Tribes Helenieae and Heliantheae. In K. Bremer, Asteraceae, cladistics and classification. Timber Press, Portland, Oregon
  • LINNAEUS, C. VON. 1753. Species plantarum. Laurentius Salvius, Stockholm
  • LINNAEUS, C. VON. 1754. Genera plantarum, edn 5. Laurentius Salvius, Stockholm
  • OLIVER, D & HIERN, W.P. 1877. Compositae. Flora of tropical Africa 3
  • PHILLIPS, E.P. 1951. The genera of South African flowering plants, edn 2. Memoirs of the Botanical Survey of South Africa No. 25
  • WILD, H. 1967. The Compositae of the Flora zambesiaca area, 1. Kirkia 6