![]() ![]() 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. Īmong 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. Atriplex rosea is called the tumbling oracle or tumbling orach. Other members of the Amaranthaceae (s.l.) that form tumbleweeds include Kochia species, Cycloloma atriplicifolium, and Corispermum hyssopifolium, which are called plains tumbleweed. Brunsvigia bosmaniae in flower in the veld, showing the globular umbels of tumbleweed Amaryllidaceae Mass of Salsola tumbleweeds caught behind a fence Anastatica, a North African desert tumbleweed Selaginella lepidophylla, a North American desert tumbleweed Though it is a troublesome weed, Kali tragus also provides useful livestock forage on arid rangelands. 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. It is said to have arrived in the United States in shipments of flax seeds to South Dakota, perhaps about 1870. 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. Kali tragus is the so-called "Russian thistle". In the cinema genre of Westerns, they have long been symbols of frontier areas. 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. broadly defined to include Chenopodiaceae), several annual species of the genus Kali are tumbleweeds. ![]() Amaranthaceae (including Chenopodiaceae).Tumbleweeds have been recorded in the following plant groups: Many tumbleweeds establish themselves on broken soil as opportunistic agricultural weeds. The tumbleweed dispersal strategies are unusual among plants most species disperse their seeds by other mechanisms. Young plant blooming in the Mojave in April, after an extremely wet winter season Plants that form tumbleweeds A Kali tragus tumbleweed caught against a fence The tumbleweed diaspore disperses seeds, but the tumbleweed strategy 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. In the latter case, many species of tumbleweed open mechanically, releasing their seeds as they swell when they absorb water. Īpart 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 moist location. Xerophyte tumbleweed species occur most commonly in steppe and arid ecosystems, where frequent wind and the open environment permit rolling without prohibitive obstruction. 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. It is a diaspore that, once mature and dry, detaches from its root or stem and rolls due to the force of the wind. For other uses, see Tumbleweed (disambiguation).Ī tumbleweed is a structural part of the above-ground anatomy of a number of species of plants. ![]() ![]() For the most conspicuous species colloquially called tumbleweed in the U.S., see Kali tragus. This article is about a lifestyle of certain plants. ![]()
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