THISTLE
· Thistle
Thistle is that the common name of a bunch of flowering plants defined by leaves with sharp prickles on the margins, largely within the family Compositae. Prickles occur all over the plant – on the stem and flat parts of leaves. They are associate degree adaptation that protects the plant from being eaten by herbivores. Typically, Associate in Nursing bract with a clasping form of a cup or urn subtends every of a thistle's flowerheads.
The term weed is typically taken to mean specifically those plants within the tribe Cardueae (synonym: Cynareae),[1] particularly the genera asterid dicot genus, Cirsium, and Onopordum.[2] However, plants outside this tribe are sometimes known as thistles, and if this can be done thistles would type a polyphyletic cluster.
A weed is that the floral emblem of French region and Scotland, also because the emblem of the Encyclopædia Britannica.
Thistles, although one restricts the term to members of the aster family, area unit too varied a bunch for generalisation; several area unit hard weeds, together with some invasive species of Cirsium, Carduus, Silybum and Onopordum.[3] Typical adverse effects are competition with crops and interference with grazing in pastures, where dense growths of spiny vegetation suppress forage plants and repel grazing animals from eating either the thistle plants or neighbouring forage. Some species, though not intensely toxic, do have an effect on the health of animals that swallow quite tiny amounts of the fabric.[4][5]
Conversely but, the genus Cynara includes businessly necessary species of artichoke and a few species considered major weeds area unit business sources of vegetable organic compound employed in commercial cheese creating.[6] equally, some species of Silybum that occur as weeds, are cultivated for seeds that yield oil and pharmaceutical compounds like Silibinin.[7][8][9]
Other thistles that nominally area unit weeds square measure necessary honey plants, each as bee fodder normally, and as sources of luxury monofloral honey products.
· Ecology
Thistle flowers area unit favorite nectar sources of the pearl-bordered fritillary, small pearl-bordered fritillary, high brown fritillary, and dark green fritillary butterflies.[12] Thistles (and thistle-seed feeders) also attract goldfinches.
Some thistles (for example Cirsium vulgare, native to Eurasia), have been widely introduced outside their native range.[13] Control measures include Trichosirocalus weevils, but a problem with this approach, at least in North America, is that the introduced weevils could have an effect on native thistles a minimum of the maximum amount because the desired targets.[14]
Thistles are aforesaid to be important nectar sources for pollinators. Some ecological organizations, such as the Xerces Society, have attempted to raise awareness of their benefits, to counteract the general agricultural and home garden labeling of thistles as unwanted weeds. The monarch, Danaus plexippus for instance, was highlighted as traditionally relying upon taller large-flowered thistle species such as Tall thistle, Cirsium altissimum, for its migration.[15] Although such organizations focus on the benefits of native thistles, certain non-native thistles, such as Cirsium vulgare in North America, may provide similar benefits to wildlife. Some grassland and flowering plant seed production corporations offer bulk seed for native North yank weed species, for life environment restoration, though accessibility tends to be low. Thistles area unit notably valued by bumblebees for his or her high nectar production. Cirsium vulgare stratified within the prime ten for nectar production in a very United Kingdom plants survey conducted by the AgriLand project that is supported by the united kingdom Insect Pollinators Initiative.
· Medical uses
Maud Grieve recorded that Pliny and medieval writers had thought it might come hair to bald heads which within the early fashionable amount it had been believed to be a remedy for headaches, plague, canker sores, vertigo, and jaundice.
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