Salsola tragus
Encyclopedia
Kali tragus is a species of flowering plant in the amaranth family
known by the common name prickly Russian thistle, or simply Russian thistle. It is perhaps the most common species of tumbleweed
, and may be known by this general name. This plant is native to Eurasia but it has long been present in North America as an introduced species
and a common weed
of disturbed habitat; it is also naturalized throughout Central and South America and in parts of southern Africa and Australia. It was probably first introduced to the United States when a shipment of flaxseed
from Russia was contaminated with its seed and delivered to South Dakota
. It now occupies a great number of habitat types.
This is an annual herb forming a rounded, brambly clump of intricately branched, erect, curving stems growing up to a meter long. The green to red stems are hairless to hairy. They are lined with rigid, leathery, needlelike, spine-tipped leaves up to 5 centimeters long. The inflorescence
is an interrupted series of flowers, with one flower and a spiny bract
per leaf axil. The flower is surrounded by a disclike array of wide, winged sepal
s which are whitish to bright pink in color. A large plant can produce 100,000 minute seeds.
The plant dries out as the fruits develop, then breaks off at the base of the stem and is carried about by the wind, the dry fruits and seeds dropping off as it rolls. This is the plant's method of biological dispersal
.
Amaranthaceae
The flowering plant family Amaranthaceae, the Amaranth family, contains about 176 genera and 2,400 species.- Description :Most of these species are herbs or subshrubs; very few are trees or climbers. Some species are succulent....
known by the common name prickly Russian thistle, or simply Russian thistle. It is perhaps the most common species of tumbleweed
Tumbleweed
A tumbleweed is the above-ground part of a plant that, once mature and dry, disengages from the root and tumbles away in the wind. Usually, the tumbleweed is the entire plant apart from the roots, but in a few species it is a flower cluster. The tumbleweed habit is most common in steppe and desert...
, and may be known by this general name. This plant is native to Eurasia but it has long been present in North America as an introduced species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
and a common weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
of disturbed habitat; it is also naturalized throughout Central and South America and in parts of southern Africa and Australia. It was probably first introduced to the United States when a shipment of flaxseed
Flax
Flax is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent...
from Russia was contaminated with its seed and delivered to South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
. It now occupies a great number of habitat types.
This is an annual herb forming a rounded, brambly clump of intricately branched, erect, curving stems growing up to a meter long. The green to red stems are hairless to hairy. They are lined with rigid, leathery, needlelike, spine-tipped leaves up to 5 centimeters long. The inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is an interrupted series of flowers, with one flower and a spiny bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
per leaf axil. The flower is surrounded by a disclike array of wide, winged sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s which are whitish to bright pink in color. A large plant can produce 100,000 minute seeds.
The plant dries out as the fruits develop, then breaks off at the base of the stem and is carried about by the wind, the dry fruits and seeds dropping off as it rolls. This is the plant's method of biological dispersal
Biological dispersal
Biological dispersal refers to species movement away from an existing population or away from the parent organism. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for individual fitness, but also for population dynamics, population...
.