''Matricaria'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of flowering plants in the chamomile tribe within the sunflower family. Some of the species have the common name of "mayweed", but this name also refers to plants not in this genus.

Description

Their many-branched stems are prostrate to erect,

glabrous Glabrousness () is the technical term for a lack of hair, down, setae, trichomes, or other such covering. A glabrous surface may be a natural characteristic of all or part of a plant or animal, or be due to loss because of a physical condition, ...

, and very leafy. Their bipinnate

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

have numerous linear, narrowly lobed leaflets.Flora of North America, Vol. 19, 20 and 21 Page 540 Mayweed, chamomile, matricary, matricaire, chamomille ''Matricaria'' Linnaeus, Sp. Pl. 2: 890. 1753; Gen. Pl. ed. 5, 380. 1754
The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are radially symmetrical. The greenish-yellow capitula are semi-spherical. The white ray florets can be present (''M. recutita'') or lacking (''M. discoidea''). The disc florets are 4- to 5-dentate. The receptacle is 2–3 times as high as wide. The pappus may be crown-shaped and short, or lacking.

Taxonomy

The

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

of ''Matricaria'' is controversial and very confused. Several species are classified either in '' Tripleurospermum'' or ''Matricaria'' depending on the interpretation of the author. The distinction is made according to the number of the seed ribs: ''Tripleurospermum'' has one adaxial and two lateral seed ribs, while ''Matricaria'' has four or five adaxial seed ribs. ; Species

Distribution and habitat

Most are very common in the temperate regions of Eurasia and North America, as well as in northern and southern

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

, with some also being naturalised in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. '' Matricaria occidentalis'' is native to North America; other species have been introduced there.Altervista Flora Italiana, genere ''Matricaria''
includes photos and distribution maps. These are hardy, pleasantly

aromatic In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated system, conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugati ...

annuals, growing along roadsides in

ruderal A ruderal species is a plant species that is first to colonize disturbed lands. The disturbance may be natural for example, wildfires or avalanchesor the consequences of human activities, such as construction ( of roads, of buildings, mining, e ...

communities and in fallow land rich in nutrients. Though many are considered nuisance

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

s, they are suitable for rock gardens and herb gardens, and as border plants.

Ecology

''Matricaria'' species are used as food plants by the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e of some

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

species (

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...

s) including lime-speck pug.

Uses

The

extract An extract (essence) is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol, oil or water. Extracts may be sold as tinctures or absolutes or dried and powdered. The aromatic principles of ma ...

of '' Matricaria chamomilla (or recutita)'' (German chamomile) is taken as a strong tea. It has been used in

herbal medicine Herbal medicine (also called herbalism, phytomedicine or phytotherapy) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. Scientific evidence for the effectiveness of many herbal treatments ...

as a carminative and anti-inflammatory. It is also used in ointments and lotions, and as a mouthwash against infections of mouth and gums. Aromatherapy uses two essential oils of chamomile: the "true chamomile" oil (or German chamomile oil, from ''M. recutita'') and the Roman chamomile oil (from '' Chamaemelum nobile'').

References

External links

* {{Authority control Anthemideae Asteraceae genera