Sonchus
Encyclopedia
Sonchus is a genus of flowering plants in the daisy family Asteraceae
. Most of the species are annual herbs, a few are perennial, and some (restricted to the Canary Islands
) are even woody (subgenus Dendrosonchus)
Annual herbs in the genus are known as sow thistles (less commonly hare thistles or hare lettuces). The genus is named after the Ancient Greek
for such plants. All are characterized by soft, somewhat irregularly lobed leaves
that clasp the stem and, at least initially, form a basal rosette. The stem
contains a milky sap. Flower heads
are yellow and range in size from half to one inch in diameter; the florets
are all of ray type. Sow thistles are common roadside plants, and while native to Eurasia
and tropical Africa
, they are found almost worldwide in temperate
regions. Like the true thistle
s, sow thistles are in the family Asteraceae
.
Mature sow thistle stems can range from 30 cm to 2 m (1 to 6 feet) tall, depending upon species and growing conditions. Colouration ranges from green to purple in older plants. Sow thistles exude a milky latex
when any part of the plant is cut or damaged, and it is from this fact that the plants obtained the common name, "sow thistle", as they were fed to lactating sows
in the belief that milk
production would increase. Sow thistles are known as "milk thistles" in some regions, although true milk thistle
s belong to the genus Silybum.
Sow thistles have been used as fodder, particularly for rabbit
s, hence the other common names of "hare thistle" or "hare lettuce". They are also edible to human
s as a leaf vegetable
; old leaves and stalks can be bitter but young leaves have a flavour similar to lettuce
. Going by the name puha or rareke (raraki) it is frequently eaten in New Zealand
as a vegetable, particularly by the native Māori. When cooked the flavor is reminiscent of chard
.
In many areas sow thistles are considered noxious weeds, as they grow quickly in a wide range of conditions and their wind-borne seed
s allow them to spread rapidly. Sonchus arvensis, the perennial sow thistle, is considered the most economically detrimental, as it can crowd commercial crops
, is a heavy consumer of nitrogen
in soil
s, may deplete soil water of land left to fallow, and can regrow and sprout additional plants from its creeping root
s. However, sow thistles are easily uprooted by hand, and their soft stems present little resistance to slashing or mowing. Most livestock
will readily devour sow thistle in preference to grass
, and this lettuce-relative is edible and nutritious to humans — in fact this is the meaning of the second part of the Latin name, oleraceus.http://www.arthurleej.com/a-sowthistle.html Attempts at weed control by herbicidal use, to the neglect of other methods, may have led to a proliferation of this species in some environments.http://www.dpi.qld.gov.au/26_14471.htm
In traditional medicine, the plant has medicinal qualities, having "nearly the same properties as Dandelion and Succory"http://www.botanical.com/botanical/mgmh/s/sowthi71.html.
Sow thistles are common host plants for aphids. Gardeners may consider this a benefit or a curse; aphids may spread from sow thistle to other plants, but alternatively the sow thistle can encourage the growth of beneficial predators such as hoverflies
. In this regard sow thistles make excellent sacrificial plants. Sonchus species are used as food plants by the larva
e of some Lepidoptera
species including Broad-barred White
, Grey Chi
, The Nutmeg
, The Shark
and the tortrix moth Celypha rufana. The fly
Tephritis formosa
is known to attack the capitula
of this plant.
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
. Most of the species are annual herbs, a few are perennial, and some (restricted to the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
) are even woody (subgenus Dendrosonchus)
Annual herbs in the genus are known as sow thistles (less commonly hare thistles or hare lettuces). The genus is named after the Ancient Greek
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...
for such plants. All are characterized by soft, somewhat irregularly lobed leaves
Leaves
-History:Vocalist Arnar Gudjonsson was formerly the guitarist with Mower, and he was joined by Hallur Hallsson , Arnar Ólafsson , Bjarni Grímsson , and Andri Ásgrímsson . Late in 2001 they played with Emiliana Torrini and drew early praise from the New York Times...
that clasp the stem and, at least initially, form a basal rosette. The stem
Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
contains a milky sap. Flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
are yellow and range in size from half to one inch in diameter; the florets
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
are all of ray type. Sow thistles are common roadside plants, and while native to Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
and tropical Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, they are found almost worldwide in temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
regions. Like the true thistle
Thistle
Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles often occur all over the plant – on surfaces such as those of the stem and flat parts of leaves. These are an adaptation that protects the...
s, sow thistles are in the family Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
.
Mature sow thistle stems can range from 30 cm to 2 m (1 to 6 feet) tall, depending upon species and growing conditions. Colouration ranges from green to purple in older plants. Sow thistles exude a milky latex
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...
when any part of the plant is cut or damaged, and it is from this fact that the plants obtained the common name, "sow thistle", as they were fed to lactating sows
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...
in the belief that milk
Milk
Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...
production would increase. Sow thistles are known as "milk thistles" in some regions, although true milk thistle
Milk thistle
The milk thistle is a thistle of the genus Silybum Adans., a flowering plant of the daisy family . They are native to the Mediterranean regions of Europe, North Africa and the Middle East...
s belong to the genus Silybum.
Sow thistles have been used as fodder, particularly for rabbit
Rabbit
Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...
s, hence the other common names of "hare thistle" or "hare lettuce". They are also edible to human
Human
Humans are the only living species in the Homo genus...
s as a leaf vegetable
Leaf vegetable
Leaf vegetables, also called potherbs, green vegetables, greens, leafy greens or salad greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots...
; old leaves and stalks can be bitter but young leaves have a flavour similar to lettuce
Lettuce
Lettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. It is eaten either raw, notably in salads, sandwiches, hamburgers, tacos, and many other dishes, or cooked, as in Chinese cuisine in which the stem becomes just as important...
. Going by the name puha or rareke (raraki) it is frequently eaten in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
as a vegetable, particularly by the native Māori. When cooked the flavor is reminiscent of chard
Chard
Chard , is a leafy green vegetable often used in Mediterranean cooking. While the leaves are always green, chard stalks vary in color. Chard has been bred to have highly nutrious leaves at the expense of the root...
.
In many areas sow thistles are considered noxious weeds, as they grow quickly in a wide range of conditions and their wind-borne seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s allow them to spread rapidly. Sonchus arvensis, the perennial sow thistle, is considered the most economically detrimental, as it can crowd commercial crops
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, is a heavy consumer of nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
in soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s, may deplete soil water of land left to fallow, and can regrow and sprout additional plants from its creeping root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
s. However, sow thistles are easily uprooted by hand, and their soft stems present little resistance to slashing or mowing. Most livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
will readily devour sow thistle in preference to grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
, and this lettuce-relative is edible and nutritious to humans — in fact this is the meaning of the second part of the Latin name, oleraceus.http://www.arthurleej.com/a-sowthistle.html Attempts at weed control by herbicidal use, to the neglect of other methods, may have led to a proliferation of this species in some environments.http://www.dpi.qld.gov.au/26_14471.htm
Sow thistles are common host plants for aphids. Gardeners may consider this a benefit or a curse; aphids may spread from sow thistle to other plants, but alternatively the sow thistle can encourage the growth of beneficial predators such as hoverflies
Hoverfly
Hoverflies, sometimes called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the larvae eat a wide range of foods...
. In this regard sow thistles make excellent sacrificial plants. Sonchus species are used as food plants by the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e of some Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
species including Broad-barred White
Broad-barred White
The Broad-barred White is a moth of the family Noctuidae. It is distributed throughout Europe and is also found in Turkey, Iran, Israel, Lebanon, Syria, Kirghizia, Tajikistan, western Siberia and China....
, Grey Chi
Grey Chi
The Grey Chi is a moth of the family Noctuidae. It is distributed throughout Europe. Although it is not present in southern Spain and Greece, as well as northern Fennoscandia...
, The Nutmeg
Nutmeg (moth)
The nutmeg , also known as the clover cutworm, is a moth of the family Noctuidae. It is found throughout Europe although in the north of its range it is a summer migrant, not being able to survive the cold winters.This is a small to medium species with cryptically coloured forewings, varying from...
, The Shark
Shark (moth)
The Shark is a moth of the family Noctuidae. It is distributed throughout Europe, but has recently also been reported from North America, from the Magdalen Islands in Canada....
and the tortrix moth Celypha rufana. The fly
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
Tephritis formosa
Tephritis formosa
Tephritis formosa is a European species of tephritid fly also known by the common name Gall Fly . Adults females are about 5-6mm in length with wings of about 4-5mm, males are slightly smaller being about 4-5mm in length with wings of about 4-4.5mm...
is known to attack the capitula
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
of this plant.