Watercress or yellowcress ( Nasturtium officinale) is a species of aquatic plant flowering plant in the cabbage family, Brassicaceae.
Watercress is a rapidly growing perennial plant native to Eurasia. It is one of the oldest known consumed by humans. Watercress and many of its relatives, such as garden cress, Mustard plant, radish, and wasabi, are noteworthy for their piquant flavors.
Description
Watercress can grow up to in length.
The stems are hollow and float in water. The leaf structure is
Pinnate. Small, white,
and green
are produced in clusters and are frequently visited by insects, especially
hoverfly, such as
Eristalis flies.
Taxonomy
Watercress is listed in some sources as belonging to the genus
Rorippa, although molecular evidence shows those aquatic species with hollow stems are more closely related to
Cardamine than
Rorippa.
Despite the Latin name, watercress is not particularly closely related to the flowers popularly known as nasturtiums (
Tropaeolum majus).
T. majus belongs to the family
Tropaeolum, a
sister taxon to the Brassicaceae within the order
Brassicales.
Distribution and habitat
In some regions, watercress is regarded as a
weed,
in other regions as an aquatic
vegetable or
herb. Watercress has grown in many temperate locations worldwide.
Watercress was introduced into China through Hong Kong and Macao in the 1800s from Europe. Its cultivation also spread to highland areas in the tropical regions of Asia.
Clear fast-flowing chalk streams are the primary natural habitat for wild watercress in the United Kingdom.[ "Water-cress was traditionally picked wild from the edges of fast-flowing streams, where it can grow in thick drifts. . .by the 19th century it was certainly under small-scale cultivation, especially in areas where there were clear chalk streams, such as Wiltshire and the north Chilterns..."] Many settlements in England are named after watercress, from Old English êacerse, including Kersey, Kesgrave, Kersal, and Kershopefoot.
Health concerns
Watercress crops grown in the presence of
manure can be an environment for
such as the
liver fluke,
Fasciola hepatica.
Cultivated watercress has the advantage of being free of the liver fluke.
When introduced into non-native environments watercress can have negative impacts on native species. With the introduction of watercress, the organic matter in the sediment increases which in turn attracts predatory macroinvertebrates that feed on other plants in the environment.
By inhibiting the cytochrome P450 enzyme CYP2E1, compounds in watercress may alter drug metabolism in individuals on certain medications such as chlorzoxazone.
Due to its fast-growing nature and invasive species status, Nasturtium officinale is prohibited in Illinois.
Uses
Watercress leaves, stems, and fruit can be eaten raw.
In China watercress is often boiled alongside pork and traditional medicinal ingredients to make a wintertime
Herbal tonic soup. In
Vietnam it is generally used raw as a component in salads.
Tradition
Ancient Romans thought eating it would cure mental illness.
Twelfth-century mystic Hildegard of Bingen thought eating it steamed and drinking the water would cure jaundice or fever.
Watercress was eaten by Native Americans.
Some Native Americans used it to treat
kidney illnesses and
constipation, and it was thought by some to be an
aphrodisiac.
Early African Americans used the plant as an
abortifacient; it was believed to cause sterility as well.
Nutrition
The new tips of watercress leaves can be eaten raw or cooked,
although caution should be used when collecting these in the wild because of parasites such as
giardia.
Watercress is 95% water and has low contents of
,
protein,
fat, and
dietary fiber. A 100-gram serving of raw watercress provides , is particularly rich in
vitamin K (238% of the
Daily Value, DV), and contains significant amounts of
vitamin A,
vitamin C,
riboflavin, vitamin B
6,
calcium, and
manganese.
Phytochemicals and cooking
As a cruciferous vegetable, watercress contains
that are partly destroyed by boiling, while the
bioavailability of its
is slightly increased by cooking. Steaming or
microwave oven retains these
a bit better than boiling.
Cultivation
Watercress cultivation is practical on both a large scale and a garden scale. Being semi-aquatic, watercress is well-suited to
hydroponic cultivation, thriving best in water that is slightly
alkaline. It is frequently produced around the headwaters of
. In many local markets, the demand for hydroponically grown watercress exceeds supply, partly because cress leaves are unsuitable for distribution in dried form and can be stored fresh for only 2–3 days.
Also sold as Sprouting, the edible shoots are harvested days after germination. If unharvested, watercress can grow to a height of .
In the United Kingdom watercress was first commercially cultivated in 1808 by the horticulturist William Bradbery along the River Ebbsfleet in Kent. Historically important areas of cultivation also included Hampshire, Stamford and Watercress Wildlife Site at St Albans. Watercress is now grown in several counties, most notably Hampshire, Dorset, Wiltshire and Hertfordshire. New Alresford in Hampshire is considered to be the nation's watercress capital,
See also
Sources
External links
