Matricaria discoidea de Candolle

Remark The words or terms in red actually dark orange) in the text are defined in a glossary.


jul_02_07.gthmb can't be loaded. Matricaria discoidea commonly known as the pineapple weed is a low growing annual plant native to northwestern North America and the north-east of Asia (It is possible that this plant was originally brought to North American from NE Asia by Amerindians). It has spread to eastern and northern North America and has become a cosmopolitan weed. The root system consists of a branching taproot. Matricaria discoidea can grow in dense mats in the well trodden areas. It is aromatic, with a pineapple odor when bruised. Its number of chromosomes (2n) is 18.

The species belongs to the Asteraceae family.

Name

In Latin, one of the meanings of matrix is the womb; the name Matricaria was given to the genus because Matricaria recutita (the chamomile) was widely used to treat such gynecologic complaints as menstrual cramps and sleep disorders related to premenstrual syndrome. Matricaria recutita has been found to contain fairly strong antispasmodic and anti-inflammatory constituents and is particularly effective in treating stomach and intestinal cramps.

In classical Greek, δισκοειδησ (diskoeidês) means discoid (shaped like a disk) a term that is derived from δισκοσ (diskos) that means disk and from ειδοσ (eidos) that means shape, external aspect. The epithet refers then to the capitula of Matricaria discoidea that are without rays, i.e. discoid.

Common names

Some of the vernacular names of Matricaria discoidea are Pineappleweed, Pineapple Weed, Disc Mayweed, Rayless chamomile. The French vernacular name are Matricaire odorante, Matricaire sans ligules, Matricaire fausse-camomille, Matricaire parfumée, Matricaire en disque.

Synonyms

draw_a.jpg can't be loaded. Matricaria discoidea has also been known as:

Identification

Matricaria discoidea is easy to identify by its highly dissected foliage, its small size, its greenish-yellow flower heads without ray florets and the pineapple scent of its foliage. It cannot be confused with Matricaria chamomilla that is also found in Québec, since the later one has white rays florets while the former has none.

Description

Stems

Leaves

Flower heads

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Fruits

Habitat

Matricaria discoidea natural habitat is ill-defined because the species has become ruderal even in its native range. It grows well in disturbed areas, especially those with poor, compacted soil. It can be seen blooming on footpaths, roadsides, cultivated and abandoned fields and gardens, irrigation ditches, stream banks, and similar places. It grows best in full sun.

Distribution

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Matricaria discoidea is found in all the Canadian provinces nearly all the Canadian Territories; it is also found in nearly all states in the USA, including Alaska, but for Florida, Alabama and Georgia. The maps shows the worldwide distribution of the plant. (One of the synonyms of Matricaria discoidea is Chamomilla suaveolens).

Notes

The flowers of Matricaria discoidea exude a chamomile or pineapple aroma when crushed. They are edible and have been used in salads (although they may become bitter by the time the plant blooms) and to make a herbal tea.

Matricaria discoidea has also been used for medicinal purposes, including for relief of gastrointestinal upset, infected sores, fevers, and postpartum anemia. It was often used by the American Indians, at times as a panacea. The Aleut (from the Aleutian Islands) used an infusion of the leaves for stomach pains, especially from gas, and as a laxative and a tonic. The Blackfoot and Cahuilla used a decoction of the plant and flowers for diarrhea. The Cheyenne used it in their Sun Dance ceremony and as an ingredient in many medicines. The Eskimo used the plant in steambath for its pleasant odor and for medicinal purposes. The Montana Indians used an infusion of herb for building up blood at childbirth and delivering the placenta, and for young girls for menstrual cramps. Etc.

Matricaria discoidea is closely related to plants of the Ambrosia genus (ragweed, and can cause similar allergic reactions in susceptible individuals.

Gallery

The photos of the gallery were taken either with one of the following: Minolta DiMAGE 7, Canon PowerShot A530, Canon Xt Rebel, usually with the EF-S60mm f/2.8 Macro USM objective, Fujifilm A 610 and EPSON Perfection 1650 (scanner). The title in the window shows the date when the picture was taken, i.e. jan_30_06... would mean that the photo was taken on the 30th of January, the 06 is for the 6th picture taken that day. The month, day and picture number might be followed by a letter which I use to identify the system used to take the picture.

Click on the thumbnails to get larger view. The original photos are usually in TIFF format, the photos shown are generally in JPEG format, often of dimensions one half (surface one quarter) for loading time reduction.

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