page_title: Tumbleweed
section_title: Plants that form tumbleweeds
hierarchical_section_title: Tumbleweed / Plants that form tumbleweeds
caption_attribution_description: English: Tumbleweeds (Salsola kali) on fence, near Winton, Outback Australia
context_page_description: A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants, a diaspore that, once it is mature and dry, detaches from its root or stem, and rolls due to the force of the wind. In most such species, the tumbleweed is in effect the entire plant apart from the root system, but in other plants, a hollow fruit or inflorescence might detach instead. Xerophyte tumbleweed species occur most commonly in steppe and arid ecosystems, where frequent wind and the open environment permit rolling without prohibitive obstruction.
  Apart from its primary vascular system and roots, the tissues of the tumbleweed structure are dead; their death is functional because it is necessary for the structure to degrade gradually and fall apart so that its seeds or spores can escape during the tumbling, or germinate after the tumbleweed has come to rest in a wet location. In the latter case, many species of tumbleweed open mechanically, releasing their seeds as they swell when they absorb water.
context_section_description: The tumbleweed dispersal strategies are unusual among plants; most species disperse their seeds by other mechanisms. Many tumbleweeds are ruderal species, opportunistic agricultural weeds. Tumbleweeds have been recorded in the following plant groups:
  Amaranthaceae (including Chenopodiaceae)
  Amaryllidaceae
  Asphodelaceae
  Asteraceae
  Brassicaceae
  Boraginaceae
  Caryophyllaceae
  Fabaceae
  Lamiaceae
  Poaceae
  In the family Amaranthaceae s.l. (i.e. broadly defined to include Chenopodiaceae), several annual species of the genus Kali are tumbleweeds.  They are thought to be native to Eurasia, but when their seeds entered North America in shipments of agricultural seeds, they became naturalized in large areas. In the cinema genre of Westerns, they have long been symbols of frontier areas. Kali tragus is the so-called  "Russian thistle". It is an annual plant that breaks off at the stem base when it dies, and forms a tumbleweed, dispersing its seeds as the wind rolls it along.  It is said to have arrived in the United States in shipments of flax seeds to South Dakota, perhaps about 1870. It now is a noxious weed throughout North America, dominating disturbed habitats such as roadsides, cultivated fields, eroded slopes, and arid regions with sparse vegetation. Though it is a troublesome weed, Kali tragus also provides useful livestock forage on arid rangelands.
  Other members of the Amaranthaceae (s.l.) that form tumbleweeds include  Kochia species, Cycloloma atriplicifolium, and Corispermum hyssopifolium, which are called plains tumbleweed. Atriplex rosea is called the tumbling oracle or tumbling orach.
  Among the Amaranthaceae (s.s.) that form tumbleweeds, there are several species of Amaranthus, such as Amaranthus albus, native to Central America but invasive in Europe, Asia, and Australia; and Amaranthus graecizans, native to Africa, but naturalized in North America. Amaranthus retroflexus, which is indigenous to tropical North and South America, has become nearly cosmopolitan largely as a weed, but like many other species of Amaranthus, it also is widely valued as animal forage and as human food, though it should be utilised with caution to avoid toxicity.
  Several Southern African genera in the family Amaryllidaceae produce highly optimised tumbleweeds; their inflorescences are globular umbels with long, spoke-like pedicels, either effectively at ground level, or breaking off once the stems are dry. When the seeds are about ripe, the fruit remain attached to the peduncles, but the stem of the umbel detaches, permitting the globes to roll about in the wind. The light, open, globular structures form very effective tumbleweed diaspores, dropping their seeds usually within a few days as the follicles fail under the wear of rolling. The seeds are fleshy, short-lived, and germinate rapidly where they land. Being poisonous and distasteful, they are not attractive to candidate transport animals, so the rolling diaspore is a very effective dispersal strategy for such plants. Genera with this means of seed dispersal include Ammocharis, Boophone, Crossyne and Brunsvigia.
  Some species of the Apiaceae form tumbleweeds from their flower umbels, much as some Amaryllidaceae do.
  In the Asteraceae, the knapweed Centaurea diffusa forms tumbleweeds.  It is native to Eurasia and is naturalized in much of North America. Also in the Asteraceae, Lessingia glandulifera, native to America,  sometimes forms tumbleweeds; it grows on sandy soils in desert areas, chaparral, and open pine forests of the western United States.
  In the Brassicaceae, Sisymbrium altissimum, Crambe maritima, Lepidium, and a resurrection plant, Anastatica form tumbleweeds.
  In the Caryophyllaceae, the garden plant "baby's-breath" (Gypsophila paniculata), produces a dry inflorescence that forms tumbleweeds. In parts of central and western North America, it has become a common weed in many locations including hayfields and pastures.
  In the legume family (Fabaceae), Baptisia tinctoria and some species of Psoralea produce tumbleweeds. In Psoralea the tumbleweed detaches from the plant by abscis
caption: Mass of Salsola tumbleweeds caught behind a fence
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