Tumbleweed

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A tumbleweed (Lechenaultia divaricata)

Several plant species that grow in arid, steppe-like environments use the wind to propagate. The structure that is pushed by the wind is usually called tumbleweed. This structure will detatch from its root or stem and will roll on the ground. In most such species, the tumbleweed consists of the whole plant apart from the root system. Sometimes, only a hollow fruit or inflorescence detaches.[1] Tumbleweed species occur most commonly in steppe and arid ecosystems, where frequent wind and the open environment permit rolling easly.[2]

Most tissues of the tumbleweed structure are dead. This needs to be the case, because the structure needs to degrade and fall apart so that its seeds or spores can escape during the tumbling. Sometimes they germinate after the tumbleweed has come to rest in a wet location. In this case, many species of tumbleweed open mechanically, releasing their seeds as they swell when they absorb water.[3]

The tumbleweed diaspore disperses seeds. This stategy is not limited to the seed plants; some species of spore-bearing cryptogams—such as Selaginella—form tumbleweeds, and some fungi that resemble puffballs dry out, break free of their attachments and are similarly tumbled by the wind, dispersing spores as they go.[4][5]

Young tumbleweed blooming in the Mojave desert in April, after an extremely wet winter season

Examples[change | change source]

References[change | change source]

  1. William Francis Ganong (1921). A Textbook of Botany for Colleges. MacMillan Co. p. 359.
  2. Dirk V. Baker (2007). Dispersal of an Invasive Tumbleweed. ProQuest. pp. 90–. ISBN 978-0-549-44310-0.[permanent dead link]
  3. W. F. Ganong (1896). "An outline of phytobiology". Bulletin of the Natural History Society of New Brunswick. 13: 3–26, page 1 errata. page 16
  4. Orson K. Miller, Jr.; Hope H. Miller (1988). Gasteromycetes: Morphological and Developmental Features with Keys to the Orders, Families, and Genera. Mad River PressInc. ISBN 978-0-916422-74-5.
  5. Bulletin. Ohio State University. 1928.

Other websites[change | change source]