Scleranthus annuus | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Caryophyllales |
Family: | Caryophyllaceae |
Genus: | Scleranthus |
Species: | S. annuus |
Binomial name | |
Scleranthus annuus | |
Scleranthus annuus is a species of flowering plant in the family Caryophyllaceae known by the common names German knotweed and annual knawel. [1] It is native to Europe, Asia, and North Africa, and it is known throughout the rest of the temperate world as an introduced species and a common weed. It grows in many types of habitat, often in disturbed areas.
Scleranthus annuus is an annual or biennial herb with low, much-branched spreading stems up to 15 cm (6 in) long growing from a taproot. The leaves are needle-like or linear in shape with sharp, stiff points. They are oppositely arranged in pairs about the stem and are fused together at the bases. Flowers occur in pairs or small clusters of up to five. The flowers lack petals but have bell-shaped calyces of green petal-shaped sepals. [1] [2]
It grows in soil pockets among rocks, on bare places, on disturbed sandy soil on heaths, in arable fields, in sand pits, in quarries, and occasionally on shingle on the coast or beside rivers. [3]
The plant seems to have three different life strategies; some seeds germinate in the autumn and overwinter as small seedlings; others overwinter as seeds and germinate in the spring, flowering the same year; and some germinate in the spring but do not flower until the following year. The flowering period for all three groups extends from late May to late August. The flowers make little effort to attract insects for pollination (no showy petals, little nectar), and most are self-pollinated. [1]
This plant is in decline in many of its previous habitats and is no longer present in many inland sites in Britain and Ireland. This may be due to changes in agriculture practices. It is listed in the Great Britain Vascular Plant Red Data List as endangered and is listed as a Northern Ireland Priority Species. [1]
Carduus nutans, with the common names musk thistle, nodding thistle, and nodding plumeless thistle, is a biennial plant in the daisy and sunflower family Asteraceae. It is native to regions of Eurasia.
Viola pedunculata, the California golden violet, Johnny jump up, or yellow pansy, is a perennial yellow wildflower of the coast and coastal ranges in California and northwestern Baja California. The common name "Johnny jump up" is usually associated with Viola tricolor however, the introduced garden annual.
Chamaenerion angustifolium is a perennial herbaceous flowering plant in the willowherb family Onagraceae. It is known in North America as fireweed, in some parts of Canada as great willowherb, in Britain and Ireland as rosebay willowherb. In the United Kingdom it is also known as bombweed, as a result of its rapid appearance on city bomb sites during the Blitz of World War II; the plant is also traditionally known as Saint Anthony's laurel. It is also known by the synonyms Chamerion angustifolium and Epilobium angustifolium. It is native throughout the temperate Northern Hemisphere, including large parts of the boreal forests.
Cirsium vulgare, the spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus Cirsium, native throughout most of Europe, Western Asia, and northwestern Africa. It is also naturalised in North America, Africa, and Australia and is an invasive weed in some areas. It is the national flower of Scotland.
Rhinanthus minor, known as yellow rattle, is a herbaceous wildflower in the genus Rhinanthus in the family Orobanchaceae. It has circumpolar distribution in Europe, Russia, western Asia, and northern North America. An annual plant, yellow rattle grows up to 10–50 centimetres (3.9–19.7 in) tall, with upright stems and opposite, simple leaves. The fruit is a dry capsule, with loose, rattling seeds.
Polygonum arenastrum, commonly known as equal-leaved knotgrass, is a summer annual flowering plant in the knotweed family Polygonaceae. Other common names include common knotweed, prostrate knotweed, mat grass, oval-leaf knotweed, stone grass, wiregrass, and door weed, as well as many others. It is native to Europe and can be found on other continents as an introduced species and a common noxious weed. Knotweed was first seen in North America in 1809 and is now seen across much of the United States and Canada.
Melilotus albus, known as honey clover, white melilot (UK), Bokhara clover (Australia), white sweetclover (USA), and sweet clover, is a nitrogen-fixing legume in the family Fabaceae. Melilotus albus is considered a valuable honey plant and source of nectar and is often grown for forage. Its characteristic sweet odor, intensified by drying, is derived from coumarin.
Platystemon is a monotypic genus of flowering plants in the poppy family containing the single species Platystemon californicus, which is known by the common name creamcups. It is native to Oregon, California, Arizona, Utah and Baja California, and is found in open grasslands and sandy soils below 6,000 feet (1,800 m) elevation.
Cerastium glomeratum is a species of flowering plant in the family Caryophyllaceae known by the common names sticky mouse-ear chickweed and clammy chickweed. It is probably native to Eurasia but it is known on most continents as an introduced species. It grows in many types of habitat. The blooming period is February, March, April, and May.
Salix scouleriana is a species of willow native to northwestern North America. Other names occasionally used include fire willow, Nuttall willow, mountain willow, and black willow.
Verbascum blattaria, the moth mullein, is a flowering biennial plant belonging to the figwort family Scrophulariaceae. A native of Eurasia and North Africa, it has naturalized in the United States and most of Canada since its introduction and has become an invasive species there. It has been declared a noxious weed by the state of Colorado.
Erigeron annuus, the annual fleabane, daisy fleabane, or eastern daisy fleabane, is a species of herbaceous, annual or biennial flowering plant in the family Asteraceae.
Amaranthus tuberculatus, commonly known as roughfruit amaranth, rough-fruited water-hemp, tall waterhemp, or common waterhemp, is a species of flowering plant. It is a summer annual broadleaf with a germination period that lasts several months. Tall waterhemp has been reported as a weed in 40 of 50 U.S. states.
Mentzelia albicaulis is a species of flowering plants in the family Loasaceae known by the common names whitestem blazingstar, white-stemmed stickleaf, and small flowered blazing star. It is native to much of western North America, where it grows in mountain, desert, and plateau habitat.
Silene noctiflora is a species of flowering plant in the family Caryophyllaceae known by the common names night-flowering catchfly, nightflowering silene and clammy cockle. It is native to Eurasia, but it is known on other continents as an introduced species and sometimes a weed. In North America, it is a common weed of grain crops in the Canadian prairie provinces and in much of the United States. It grows in fields and in other disturbed habitat.
Deinandra fasciculata, known by the common names clustered tarweed and fascicled spikeweed, is a species of flowering plant in the family Asteraceae native to western North America.
Artemisia norvegica is a species of flowering plant in the aster family known by the common names alpine sagewort, boreal sagewort, mountain sagewort, Norwegian mugwort, arctic wormwood, and spruce wormwood. It is found in cold locations in Eurasia and high altitudes and high latitudes in North America.
Axyris amaranthoides is a species of flowering plant, in the family Amaranthaceae, that has been introduced to North America. It was introduced into Manitoba in 1886 and has since spread to other provinces in Canada and the United States. Axyris amaranthoides (2n=18) is commonly known as Russian pigweed and upright axyris. The Chinese name is zhouli (轴藜).
Paysonia stonensis is a species of flowering plant in the family Brassicaceae, known by the common name Stones River bladderpod. It is endemic to Tennessee in the United States, where it is limited to Rutherford County. It grows only in the floodplains of the Stones River, and certain tributaries.
Senecio minimus, commonly known as toothed fireweed and coastal burnweed, is a species of plant in the sunflower family. It is native to Australia and New Zealand, and also naturalized on the Pacific Coast of the United States.