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Cotula coronopifolia

Small annual herb (up to 20 cm) with yellow flowers compressed like a button.

Scientific name: Cotula coronopifolia L.

Common names: brassbuttons, common brassbuttons

Family: Asteraceae (Compositae)

Status in Portugal: invasive species (listed in the Decreto-Lei nº 92/2019, 10 july)

Risk Assessment score: 16 | Value obtained according to a protocol adapted from the Australian Weed Risk Assessment (Pheloung et al. 1999), by Morais et al. (2017), according to which values above 13 mean that the species has risk of having invasive behavior in the Portuguese territory | Updated on 30/09/2017.

Last update: 09/07/2021

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Cotula coronopifolia
Family: 
Asteraceae (Compositae)
Appearence: 
Aquatic plants

How to recognise it

Annual herb with stems up to (20 cm), stoloniferous, decumbent, glabrous and aromatic.

Leaves: entire or with very little indentations, oblong, with an invaginated petiole; aromatic.

Flowers: arranged in pedunculate capitula of 5-10 mm diameter, with yellow internal flowers (of the disk) shortly pedicellate, hermaphrodite, tubular; external flowers with long pedicels, without corolla; ovate involucral bracts, and a scarious margin.

Fruits: peripheral cypselas compressed and winged; the ones from the disk are apterous.

Flowering: March to September.

 

Similar species

Although it’s not easy to confuse Cotula coronopifolia, Tanacetum vulgare L. (common tansy) has capitula that are somewhat similar, but the plant is taller, the leaves have deep indentations, and since it is not salt intolerant it tends to occur in different habitats.

 

Characteristics that aid invasion

It propagates by seed producing many seeds that are dispersed by water, and able to travel hundreds of meters per year. The seeds are viable for 1 or 2 years.

It also propagates vegetatively, through stem fragments that have great rooting ability.

Native distribution area

South Africa (Cape region).

 

Distribution in Portugal

Mainland Portugal (Minho, Douro Litoral, Beira Litoral, Estremadura, Ribatejo, Baixo Alentejo, Algarve).

 

Geographic areas where there are records of Cotula coronopifolia

Other places where the species is invasive

Europe (Spain), western USA (California), Australia.

 

Introduction reasons

Probably accidental.

 

Preferential invasion environments

It develops in humid areas, even where salinity is high; normally seen along the beaches, tide zones and estuaries. It also occurs in rice fields.

The species has adapted to several types of soils, being able to grow in acid, basic and neutral soils.

It doesn’t tolerate shade nor frost.

Impacts on ecossystems

It forms continuous mats that inhibit the development of native vegetation.

An increase in salinity may occur in soils occupied by the species, which may inhibit the development of native vegetation.

 

Economic impacts

Potentiallyit may reduce productivity in rice fields.

 

Natura 2000 Network habitats more subject to impacts

– Atlantic salt meadows (Glauco-Puccinellietalia maritimae) (1330);
– Mediterranean salt meadows (Juncatalia maritimi) (1410).

Controlling an invasive species demands a well-planned management, which includes the determination of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention priorities, selecting the adequate control methodologies and their application. Afterwards it is fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as to perform, whenever necessary, the follow-up control.

The control methodologies used for Cotula coronopifolia include:

 

Physical control (preferencial methodology)

Hand pulling: it is applied to plants of all sizes. It should be done before fruit maturation and it should be guaranteed that no roots and/or large fragments remain in the soil.

 

Chemical control

Although the application of herbicides is referred to as one of the most efficient methodologies to control the species, there is no information about its application in Portugal.

 

Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.

Dana ED, Sanz-Elorza M, Vivas S, Sobrino E (2005) Especies vegetales invasoras en Andalucía. Consejería de Medio Ambiente, Junta de Andalucía, Sevilla, 233pp.

 

 

Marchante E, Freitas H, Marchante H (2008) Guia prático para a identificação de plantas invasoras de Portugal Continental. Imprensa da Universidade de Coimbra, Coimbra, 183pp.