A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants. It is a diaspore that, once 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. [1] Xerophyte tumbleweed species occur most commonly in steppe and arid ecosystems, where frequent wind and the open environment permit rolling without prohibitive obstruction. [2]
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 moist location. In the latter case, many species of tumbleweed open mechanically, releasing their seeds as they swell when they absorb water. [3]
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. [4] [5]
The tumbleweed dispersal strategies are unusual among plants; most species disperse their seeds by other mechanisms. Many tumbleweeds establish themselves on broken soil as opportunistic agricultural weeds. Tumbleweeds have been recorded in the following plant groups: [6]
In the family Amaranthaceae s.l. (i.e. broadly defined to include Chenopodiaceae), several annual species of the genus Salsola 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. Salsola 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. [7] It is said to have arrived in the United States in shipments of flax seeds to South Dakota, perhaps about 1870. [8] 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. [9]
Other members of the Amaranthaceae (s.l.) that form tumbleweeds include Kochia species, [10] [11] Cycloloma atriplicifolium , and Corispermum hyssopifolium, [10] which are called plains tumbleweed. [12] Atriplex rosea is called the tumbling oracle or tumbling orach. [13] [14]
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. [15] 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. [16]
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 . [17]
Some species of the Apiaceae form tumbleweeds from their flower umbels, much as some Amaryllidaceae do. [1]
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. [18]
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. [19]
In the legume family (Fabaceae), Baptisia tinctoria and some species of Psoralea produce tumbleweeds. In Psoralea the tumbleweed detaches from the plant by abscission of the stem. [20]
In the Plantaginaceae, Plantago cretica forms tumbleweeds.
Inflorescences that act as tumbling diaspores occur in some grasses, including Schedonnardus paniculatus and some species of Eragrostis and Aristida . [21] In these plants, the inflorescences break off and tumble in the wind instead of the whole plant, much as happens in some of the Apiaceae and Amaryllidaceae. The species of Spinifex from Southeast Asia are prominent examples of this dispersal adaptation. [22] These grasses are often called tumble-grasses, including such species as Panicum capillare and Eragrostis pectinacea in the United States. [23]
In the Solanaceae, Solanum rostratum [10] forms tumbleweeds.
Wind dispersed fruits that tumble or roll on the ground, sometimes known as "tumble fruits", are rare. Some are technically achenes. Highly inflated indehiscent fruits that may facilitate tumbling include Alyssopsis , Coluteocarpus , Physoptychis , Sutherlandia , and Physaria . [24]
Very similar in habit to Anastatica, but practically unrelated, are the spore-bearing Selaginella lepidophylla (a lycopod) and earthstar mushroom family (Geastraceae). All of these curl into a ball when dry and uncurl when moistened.
Bovista , a genus of puffball, uses essentially the same dispersal strategy.
The United States Department of Agriculture classified the ubiquitous tumbleweeds as a non-native and extremely invasive plant in the United States. They are considered noxious in nature and detrimental in many ways. Tumbleweeds thrive in disturbed soil and are a major contributor to native plant extinctions and wildfires, being highly flammable and bouncing over or rapidly growing in land cleared of vegetation between fields or areas of forest as firebreaks. Despite over a century of cooperation between Mexican, Canadian, and US governments to combat the species, tumbleweeds are found in most regions of North America. [25]
Some ruderal species that disperse as tumbleweeds are serious weeds that significantly promote wind erosion in open regions.[ citation needed ] Their effects are particularly harmful to dry-land agricultural operations where the outside application of additional moisture is not practicable. One study showed that a single Russian thistle can remove up to 170 L (44 US gallons) of water from the soil in competition with a wheat crop in one year. [26] The amount of water removed from fallow land more subject to erosion would be even more damaging.
It sometimes happens that species of large tumbleweed, especially if thorny, can form aggregations that are physically hazardous and can block roads and cover buildings and vehicles. This can happen where fences and similar obstacles cause the accumulation, but the weeds can also entangle each other until they form piles that can no longer roll. Such piles can be a serious threat to trapped vehicles or buildings and their occupants, particularly because they are dry and flammable. Examples of enveloped buildings and vehicles have been documented mainly in the Western regions of the US. In residential areas, an example was the town of Mobridge, South Dakota, where in 1989 tens of tons of large tumbleweeds ("Russian thistles") that had matured in the dry bed of nearby Lake Oahe buried many houses so deeply that mechanical equipment was necessary to remove it, release occupants and counter the fire hazard. [27] [28]
There was a significant outbreak of Panicum effusum in the Australian town of Wangaratta in February 2016 that attracted international attention. The seed heads of the weed, known locally as "hairy panic", had piled several meters deep in some places, forcing residents to spend several hours removing it to regain access to their homes. [29] [30] [31] The local council subsequently indicated it was considering attaching large vacuums to street-sweepers in an attempt to control the outbreak. [32]
On 18 April 2018, strong winds and neglected maintenance of neighboring private land brought a large number of tumbleweeds into Victorville, California. Approximately 100 to 150 homes required help from public services after their entryways were at least partly blocked. The local fire department participated in the cleanup as the influx of tumbleweeds presented both a safety and fire hazard. [33]
A similar incident occurred on 31 December 2019, when high winds dislodged a large number of tumbleweeds on the Hanford Reservation northwest of Richland, Washington. The tumbleweeds piled up 4.5 to 6 m (15 to 20 feet) deep in some areas, burying cars and trucks and closing Washington State Route 240 for ten hours while road crews used snowplows to remove the tumbleweeds. [34] [35] [ better source needed ]
Tumbleweeds have been observed causing problems with wastewater treatment plants. In some cases of inadequate fencing, they can get entangled in electromechanical equipment such as clarifiers and mechanical aerators leading to increased energy use and labor cost associated with operating and cleaning. [36]
Originating in the Western genre, tumbleweeds are frequently used as a trope in films and TV shows. In shots set in a desolate and deserted place, or generally in a locale with little activity, tumbleweeds may be seen rolling across the scenery. [37] [38] [ better source needed ] This motif has become clichéd, [39] with the result that it is nowadays primarily used with humoristic intent, for example when a short but embarrassing moment of silence occurs during a scene. One of the best-known uses of tumbleweed in cinema is in the opening sequence of The Big Lebowski (1998), where it symbolizes the "drifting" nature of the main character. [40] [ better source needed ]
Bramblin and Brambleghast are Pokémon based on tumbleweeds.
Once dry and uprooted, tumbleweeds form steppicursors [41] that, driven by the wind, roll on the lands of Southern California, Arizona, Nevada, Utah, New Mexico, Texas, northwestern Mexico, and most of the Mexican territory just south of the border. In the area of Mexicali they are called cachanillas, which is also a demonym for those born and residing in that capital city of Baja California.
Amaranthus is a cosmopolitan group of more than 50 species which make up the genus of annual or short-lived perennial plants collectively known as amaranths. Some of the better known names include "prostrate pigweed" and "love lies bleeding". Some amaranth species are cultivated as leaf vegetables, pseudocereals, and ornamental plants.
Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus Amaranthus. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it the most species-rich lineage within its parent order, Caryophyllales.
An achene, also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent. Achenes contain a single seed that nearly fills the pericarp, but does not adhere to it. In many species, what is called the "seed" is an achene, a fruit containing the seed. The seed-like appearance is owed to the hardening of the fruit wall (pericarp), which encloses the solitary seed so closely as to seem like a seed coat.
Erigeron bonariensis is a species in the family Asteraceae, found throughout the tropics and subtropics as a pioneer plant; its precise origin is unknown, but most likely it stems from Central America or South America. It has become naturalized in many other regions, including North America, Europe and Australia.
Halogeton glomeratus is a species of flowering plant in the family Amaranthaceae known by the common names saltlover, Aral barilla, and halogeton. It is native to Russia, Central Asia and China, but the plant is probably better known in the western United States, where it is an introduced species and a notorious noxious weed. This annual herb is a hardy halophyte, thriving in soils far too saline to support many other plants. It also grows in alkali soils such as those on alkali flats and disturbed, barren habitat. It can be found in sagebrush and shadscale habitat, and it grows well in areas with cold winters.
Amaranthus retroflexus is a species of flowering plant in the family Amaranthaceae with several common names, including red-root amaranth, redroot pigweed, red-rooted pigweed, common amaranth, pigweed amaranth, and common tumbleweed.
Amaranthus albus is an annual species of flowering plant native to the Americas. Common names include common tumbleweed, tumble pigweed, tumbleweed, prostrate pigweed, pigweed amaranth, white amaranth and white pigweed.
Beta is a genus in the flowering plant family Amaranthaceae. The best known member is the common beet, Beta vulgaris, but several other species are recognised. Almost all have common names containing the word "beet". Wild Beta species can be found throughout the Atlantic coast of Europe, the Mediterranean coastline, the Near East, and parts of Asia including India.
Salsola kali is the restored botanical name for a species of flowering plants in the amaranth family. It is native to the Northern African and European Atlantic coasts to the Mediterranean. It is an annual plant which grows primarily in the temperate biome.
Anemone virginiana is an upright growing herbaceous species of flowering plant in the buttercup family Ranunculaceae. It is a perennial that grows 30–80 centimetres (12–31 in) tall, flowering from May until July. The flowers are white or greenish-white. After flowering, the fruits are produced in dense rounded thimble-shaped spikes 15–35 millimetres (0.59–1.38 in) long and 12 millimetres (0.47 in) wide. When the fruits, called achenes, are ripe they have gray-white colored, densely woolly styles, that allow them to blow away in the wind. The leaf structure is whorled halfway up the stem and each individual leaf appears to be deeply cut. It is native from eastern North America, where it is found growing in dry or open woods. This plant can be found in 38 out of the 50 states in the United States and is located anywhere from Maine to Minnesota going west, and found as far south as Georgia and Louisiana.
Salsola is a genus of the subfamily Salsoloideae in the family Amaranthaceae. The genus sensu stricto is distributed in Australia, central and southwestern Asia, North Africa, and the Mediterranean. Common names of various members of this genus and related genera are saltwort and tumbleweed or roly-poly. The genus name Salsola is from the Latin salsus, meaning 'salty'.
A tumbleweed is a kind of plant habit or structure.
Dysphania atriplicifolia is species of flowering plant known by the common names winged pigweed, tumble ringwing, plains tumbleweed, and tumble-weed. This plant is native to central North America, but it is spreading and has been occasionally reported in far-flung areas from California to Maine to the Canadian prairie. It is considered an introduced species outside of central North America. This is a bushy annual herb forming a rounded pale green clump which may exceed 0.5 m in height. It is very intricately branched, with toothed leaves occurring near the base. The spreading stems bear widely spaced flowers are small immature fruits fringed with a nearly transparent membranous wing. In autumn, the plant forms a tumbleweed. The fruit is a utricle about 2 millimeters long containing a single seed.
Krascheninnikovia is a genus of flowering plants in the subfamily Chenopodioideae of the family Amaranthaceae known as winterfat, so-called because it is a nutritious livestock forage. They are known from Eurasia and western North America. These are hairy perennials or small shrubs which may be monoecious or dioecious. They bear spike inflorescences of woolly flowers.
In botany, a diaspore is a plant dispersal unit consisting of a seed or spore plus any additional tissues that assist dispersal. In some flowering plants, the diaspore is a seed and fruit together, or a seed and elaiosome. In a few plants, the diaspore is most or all of the plant, and is known as a tumbleweed.
Salsola tragus, often known by its synonym Kali tragus is a species of flowering plant in the family Amaranthaceae. It is known by various common names such as prickly Russian thistle, windwitch, or common saltwort. It is widely known simply as tumbleweed because, in many regions of the United States, it is the most common and most conspicuous plant species that produces tumbleweeds. Informally, it may be known as "'Kali or Salsola": the latter being its restored genus, containing 54 other species, into which the obsolete genus Kali has been subsumed.
Bassia scoparia is a large annual herb in the family Amaranthaceae native to Eurasia. It has been introduced to many parts of North America, where it is found in grassland, prairie, and desert shrub ecosystems. Its common names include summer cypress, mock-cypress, kochia, belvedere, World's Fair plant, burningbush, Mexican firebrush, and Mexican fireweed, the provenance of the latter three names being the herb's red autumn foliage.
Kali was a genus of plants in the subfamily Salsoloideae in the family Amaranthaceae, that has now been subsumed into the genus Salsola.
Bassia hyssopifolia is a species of flowering plant in the family Amaranthaceae, known by the common names five-horn smotherweed, five-hook bassia, and thorn orache. It is native to parts of Asia and Eastern Europe, and it is known on other continents as an introduced species, including North and South America and Australia. It is a weed, invasive at times.
Caroxylon imbricatum, synonym Salsola imbricata, is a small species of shrub in the family Amaranthaceae. It grows in deserts and arid regions of north Africa, the Arabian Peninsula and southwestern Asia.