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Species
Centaurea solstitialis L.
IUCN
NCBI
EOL Text
Annuals, 10–100 cm. Stems simple or often branched from base, forming rounded bushy plants, gray-tomentose. Leaves gray-tomentose and scabrous to short-bristly; basal and proximal cauline petiolate or tapered to base, usually absent at anthesis, blades 5–15 cm, margins pinnately lobed or dissected; cauline long-decurrent, blades linear to oblong, 1–10 cm, entire. Heads disciform, borne singly or in open leafy arrays, long-pedunculate. Involucres ovoid, 13–17 mm, loosely cobwebby-tomentose or becoming glabrous. Principal phyllaries: bodies pale green, ovate, appendages stramineous to brown, each with palmately radiating cluster of spines, and stout central spine 10–25 mm. Inner phyllaries: appendages scarious, obtuse or abruptly spine tipped. Florets many. corollas yellow, all ± equal, 13–20 mm; sterile florets slender, inconspicuous. Cypselae dimorphic, 2–3 mm, glabrous, outer dark brown, without pappi, inner white or light brown, mottled; pappi of many white, unequal bristles 2–4 mm, fine. 2n = 16.
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| Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
| Source | http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242416255 |
Centaurea solstitialis is a serious weed pest, especially in the western United States, where it has invaded millions of acres of rangelands, and it is listed as a noxious weed in eleven western states and two Canadian provinces. It is a strong competitor in infested areas, often forming dense colonies. It is very difficult to control or eradicate once it becomes established. In addition, yellow star-thistle is poisonous to horses; when ingested over a prolonged period it causes a neurological disorder called equine nigropallidal encephalomalacia, or "chewing disease." Although its bitter taste and spiny heads usually deter grazing animals, horses sometimes will seek it out. Yellow star-thistle tends to spread in rangelands when more palatable plants are consumed.
| License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
| Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
| Source | http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242416255 |
Africa, temperate Asia and Eurasia (Balkan-Asia Minor, the Middle East and south-central Europe) Mediterranean region of southern Europe and northern Africa, especially Turkey
More info for the terms: fire use, frequency, prescribed fire
Season and frequency of burning are important in determining yellow starthistle's response to fire. Three
consecutive years of burning at early flowering stage (late June to early July
in northern California) controlled yellow starthistle and
depleted the yellow starthistle soil seed bank [33] (see Fire Case Studies). Yellow starthistle plants
may remain green for up to 4 days following burning, possibly allowing seed to
mature if burning is conducted too late in the flowering stage [53]. Prescribed fires conducted early in the spring may not be hot
enough to kill yellow starthistle and may damage desirable plants.
For further information on prescribed fire use and yellow starthistle's response to fire, see this Research Project Summary: Changes in grassland vegetation following fire in northern Idaho.
Cattle, sheep and goats will graze on yellow starthistle in early spring, and up to the bolting stage. These ruminants will not graze yellow starthistle plants after the spines emerge [82,133,139,148,149,150]. Yellow starthistle provides forage for ruminants in late spring and early summer when other green forage is generally unavailable [150]. Yellow starthistle is toxic to horses, causing a neurological disease called equine nigropallidal encephalomalacia, or "chewing disease" with prolonged ingestion. Poisoning is most likely when yellow starthistle is the only feed available (e.g. on poor condition range) or when yellow starthistle is a substantial contaminant of dried hay. In some cases, horses acquire a taste for yellow starthistle and seek it out even when other forage is available [98]. Other animals (e.g. mules and burros) are not susceptible to the toxic effects [24,30].
Yellow starthistle foliage may be eaten by grasshoppers, and yellow starthistle seeds are consumed by several species of birds including ring-necked pheasants, California quail, house finches, and American goldfinches [32,117].
Mediterranean region and Sinai.
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| Rights holder/Author | Bibliotheca Alexandrina, BA Cultnat, Bibliotheca Alexandrina - EOL Ar |
| Source | http://lifedesk.bibalex.org/ba/pages/2322 |
More info for the term: competition
Field studies suggest that fire stimulates germination of yellow starthistle seed in the soil seed bank, reduces competition in the plant community, reduces the thatch layer, and exposes mineral soil. Yellow starthistle plants that germinate following fire may grow larger and have more flowerheads the following season [53]. Sheley and others [133] suggest that "in most cases, burning increases plant size and seed production by releasing nutrients tied up in plant material", although they cite no examples.
It has been suggested that the nutritional value of yellow starthistle is low,
and that cattle subsisting on the plant will lose weight (Callihan and others
1982, as cited by [82]). The nutritional component of yellow starthistle leaves is highly digestible by
ruminants during the growing season [22], but its nutrient value declines as the plants
mature [82]. Measures of protein and acid
detergent fiber (ADF) content by Thomsen and others [148] indicate that yellow starthistle
has
acceptable nutritional value as a component of a ruminants diet. In the rosette stage protein
content ranged between 10 and 13% and acid detergent fiber (ADF) between 26 and
28%. In the
bolting to early bud stage, protein content was 11 to 13% and ADF was 28 to 32%. An analysis of the nutritional status of cattle manure in the fall
indicated that yellow starthistle infested pastures contain considerably less
crude protein and total digestible nutrients compared to uninfested pastures (Barry
1995, as cited by [30]).
Europe, Mediterranean region, western Asia, north America.
| License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
| Rights holder/Author | Bibliotheca Alexandrina, BA Cultnat, Bibliotheca Alexandrina - EOL Ar |
| Source | http://lifedesk.bibalex.org/ba/pages/2322 |
More info for the terms: prescribed fire, severity
Fire usually kills yellow starthistle plants [33], although some plants may resprout after low severity burning [85]. Fires are usually not severe enough to kill yellow starthistle seed. It has been suggested that heat from prescribed fire may stimulate germination of yellow starthistle seed in the soil [53], though as of this writing (2002) heat tolerance of yellow starthistle seed has not been studied.