Tagetes minuta
Family :
Famille :
Asteraceae
Synonym(s) :
Synonyme(s) :
Common Name(s) :
Nom(s) commun(s) :
Mexican Marigold
(English) (Wiersema & León 2016; CABI 2024))
Wild marigold (English) (CABI 2024; USDA-ARS 2024)
Muster John Henry (English) (ITIS 2024; USDA-ARS 2024)
印加孔雀草 yin jia kong que cao (FOC 1994+)
Mexikanische Studentenblume (German) (Wiersema & León 2016; USDA-ARS 2024)
Huacatay (Spanish) (CABI 2024)
Coari-bravo (Portuguese) (Wiersema & León 2016; USDA-ARS 2024)
Tagetes minuta achenes
Tagetes minuta achenes
Tagetes minuta achenes, immature
Tagetes minuta achenes
Tagetes minuta close up of achene
Tagetes minuta achene surface with hairs and gland
Tagetes minuta achene, attachment point
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Overview
Aperçu
Regulation :
Remarques Réglementation:
Regulation Notes:
Distribution :
Répartition :
Tagetes minuta is native to South America in Brazil, Bolivia, Paraguay, Uruguay, Argentina and Chile (POWO 2024). It has since been introduced into 34 countries within North America, India, Africa, Europe, Asia, and Australia (Holm et al. 1997; POWO 2024).
In the United States, Tagetes minuta has been found in California, Florida, Alabama, Georgia, North Carolina, South Carolina, Virginia, Pennsylvania, Connecticut, Massachusetts, and Hawaii (USDA-NRCS 2024).
Habitat and Crop Association :
Habitat et Cultures Associées :
The native habitat for Tagetes minuta is riparian areas and grasslands in mountainous areas of South America, and the species occupies similar high elevation habitats in northern India, East Africa, China and Taiwan (Stadler et al. 1998; Singh et al. 2003; Wang and Chen 2006; Wang et al. 2023). T. minuta appears to adapt to lower elevations and arid habitats in eastern and southern Africa with the expansion of agriculture to new areas (Holm et al. 1997; Stadler et al. 1998).
T. minuta establishes and spreads primarily through human-disturbed habitats such cultivated fields, gardens, roadsides, waste areas, animal pens, pastures and recently cleared or burned land (Holm et al. 1997; Wang et al. 2023). It was also found to spread in naturally-disturbed riparian areas and forest edges (Wang and Chen 2006; Wang et al. 2023). The species prefers well-drained, slightly acidic soil in areas with a minimum of 50 cm rainfall per year, indicating it can adapt to arid conditions (Singh et al. 2003; Wang and Chen 2006).
T. minuta has been reported as a common contaminant of Zea mays L. subsp. mays (maize), Phaseolus vulgaris L. (bean) and Triticum aestivum L. subsp. aestivum (wheat) in Africa, and a principal weed in crops such as Glycine max (L.) Merr. (soybean), Gossypium hirsutum L. (cotton), Saccharum officinarum L. (sugarcane), Pisum sativum L. (peas), and Solanum tuberosum L. (potato) in both native and introduced areas (Holm et al. 1997).
Economic Use, cultivation area, and Weed Association :
Utilisation économique, zone de culture et association de mauvaises herbes :
Tagetes minuta is cultivated primarily for the valuable “Tagetes oil” extracted from the plants (Singh et al. 2003). The species is commercially grown mainly in France, Kenya, Argentina and Australia, and was wild harvested in South Africa and northern India before domestication (Forsyth and Van Sladen 1983; Singh et al. 2003).
Tagetes oil is used primarily in perfumery and as a flavouring in food products such as beverages, candy, dairy, desserts and baked goods (Singh et al. 2003). Tagetes oil also has as antibiotic, anti-inflammatory, fungicidal and insecticidal applications (Singh et al. 2003). The plants are used as a seasoning for meats, vegetable dishes and soups in the southeastern United States, and escapes from fields likely promoted the spread of the species in the country (Neher 1968).
General Information
RENSEIGNEMENTS GÉNÉRAUX
Tagetes minuta has been used by local peoples both within the native South American range and in introduced areas (Neher 1968; Wang et al. 2023). Neher (1968) detailed the usage of T. minuta by peoples in Argentina, Brazil, and Peru. Decoctions of the plant were taken internally as a dewormer (anthelmintic), a digestive aid, as a stimulant, purgative, laxative and to produce sweating. The plant juice was applied externally, stuffed into mattresses or planted around houses as an insect repellent in Africa, and applied to hemorrhoids in Europe. Neher (1968) also documented local uses of dried stems as firewood.
Tagetes minuta is a prolific seed producer with 6000-9000 achenes produced by a single plant (Wang et al. 2023). The achenes can be transported in clothing or animal fur due to the long pappus scales (Wang et al. 2023). The optimal germination temperature was 25 °C, with the lower limit for germination at 10 °C and the upper limit 35 °C under bright light (Forsth and Van Sladen 1983). The range of temperatures for successful germination were more narrow if light was reduced, a typical response for species with a weedy habit (Forsth and Van Sladen 1983).
Extracts of T. minuta were found to inhibit germination of Raphanus sativus L. (radish) seeds by up to 65% and Lactuca sativa L. (lettuce) seeds by up to 37.5 % (Kaul and Bedi 1995).
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Tagetes minuta infestation in a field in Australia; photo also shows its typical erect and simply branched habit. Photo by Harry Rose, Wikimedia, CC BY 2.0
Identification
Identification
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Achene
Size
- Achene size from literature:
• Achene length: (4.5–)6–7+ mm (FNA 1993+)
• Achene length: 7.0-8.0 mm; width: 0.6-0.8 mm (Mukherjee and Sarkar 1999)
• Achene length: 6-8 mm (Wang and Chen 2006)
• Achene length: 6-7 mm (FOC 1994+; Singh et al. 2016)
• Achene length: 4-7 mm; width: 0.3-1 mm (Wang et al. 2023)
• Achene length: 5-8 mm (PlantNET 2024) - Pappus size from literature:
• Pappus short scale length: 0.5 – 1 mm; long scale length: 2-3+ mm (FNA 1993+; FOC 1994+)
• Pappus short scale length: 1 mm; long scale length: 3 mm (Wang et al. 2023)
• Pappus length: 0.5-3 mm (PlantNET 2024)
Shape
- Achene is linear, slightly compressed, narrower at the end opposite the pappus end (attachment scar end).
- Achene shape variable in 3D: cylindrical, oval, squarish or triangular
- Pappus scales triangular shaped and flattened
Surface Texture
- Achene surface texture reticulate, visible with 30x or higher magnification, appears sparkling under lights.
- Surface covered with long, stiff hairs forked at the tip and scattered round glands
- Pappus scales with long hairs at tip and along the edge
Colour
- Achene is dark brown or black with a yellowish brown attachment scar
- Immature achenes light brown or grey colour
- Pappus scales light brown or yellowish
- Surface hairs are shiny light brown
- Surface glands dull light brown or reddish coloured
Other Features
- Pappus composed of 5-6 long, pointed scales with 1 or 2 longer than the rest
- Attachment scar is D-shaped
Tagetes minuta achenes
- Achene size from literature:
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Seed
Size
- Seed length similar to achene length
Shape
- Seed is oblong, truncate at one end
Surface Texture
- Seed surface texture is smooth
Colour
- Seed is translucent yellowish-grey coloured
Other Features
- A thin, translucent, flexible seed coat surrounds the seed
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Embryo
Size
- Embryo partially fills the seed
Shape
- Embryo is oval shaped
Endosperm
- Endosperm scant, nutritive tissue stored in cotyledons
Other Features
- Embryo position lateral
Identification Tips
CONSEILS POUR L’IDENTIFICATION
The achenes of the Tagetes genus have a similar appearance (FNA 1993+; FOC 1994+; Singh et al. 2016):
• Narrowly triangular, wedge-shaped or spindle-shaped
• Weakly or strongly compressed
• Blackish colour with a yellowish end opposite the pappus (attachment scar end)
• Generally glabrous, or with short, forked hairs along the achene angles
• Persistent pappus of flat scales in one series
• 0-2 (-5) pappus scales longer than the rest
Achenes of T. minuta (FNA 1993+; Singh et al. 2016):
• Generally smaller than other species
• Attachment scar end black, other Tagetes species are yellowish up to ¼ achene length
• Surface densely pubescent with long brownish hairs and scattered round glands
• Pappus scales generally shorter than other species
Tagetes minuta achenes, immature
Additional Botany Information
AUTRES RENSEIGNEMENTS BOTANIQUES
Flowers/Inflorescence
- Flowers appear in simple, more or less flat-topped inflorescences (corymbiform) at the tops of stems (terminal) with usually 3 rays, each usually with few flowers on short to long stalks (peduncles) (FNA 1993+; WFO 2024).
- The collection of bracts beneath the compound flower (the involucre) are fused and narrowly cylindrical, 7–12 × 1.5–3 mm, with 3-4(5) yellow-green phyllaries (bracts) (FNA 1993+; WFO 2024) in a single row (uniseriate); hairless, with brown or orange glands (WFO 2024); they appear more like 3-5 sepals fused in a tube than most Asteraceae involucres.
- Ray flowers (look like petals) fertile female (WFO 2024); (1)2–3; pale yellow to cream-coloured, 1-3.5mm long (FNA 1993+; WFO 2024).
- Disk flowers (in center of ray flowers) 3-5(-7); yellow to dark yellow tubular corolla 3-5 mm long (FNA 1993+; WFO 2024); made of bisexual fertile flowers expanded and divided into 5 lobes above the fused tube (WFO 2024).
- Tagetes minuta is easily confused with Dyssodia papposa (Vent.) Hitchc. but the latter’s flowers smells unpleasant and its inolucres are not fused (CABI 2024).
Vegetative Features
- Plants grow 30–100(–300) cm tall (FNA 1993+; WFO 2024).
- The whole plant is highly aromatic, with all parts having embedded aromatic oil glands (WFO 2024).
- Stems are simple or branched, ribbed, hairless, glandular and aromatic, and sometimes almost woody in larger plants (WFO 2024).
- Leaves glabrous, dotted with orange aromatic glands, length: 30–300 mm; width: 7-80 mm, mostly opposite, can be alternate in the upper part, on leaf stalks (petioles), but sometimes sessile (FOC 1994+; PlantNET 2024; WFO 2024).
- Tagetes minuta is often confused with Bidens pilosa L. and can be distinguished by its taller and less branched habit and the highly aromatic oil glands in the leaves (CABI 2024).
Tagetes minuta inflorescence – showing usual terminal, few-flowered corymbiform inflorescences with pinnately divided leaves below. Photo by Guillermo Debandi, some rights reserved (CC BY) via iNaturalist.
Similar Species
ESPÈCES SEMBLABLES
Similar species are based on a study of seed morphology of various species, and those with similar dispersal units are identified. The study is limited by physical specimen and literature availability at the time of examination, and possibly impacted by the subjectivity of the authors based on their knowledge and experience. Providing similar species information for seed identification is to make users aware of similarities that could possibly result in misidentification.
Tagetes erecta L. (African marigold) and T. patula L. (French marigold)
These annual species have been cultivated for both essential oils and as ornamental plants, and are the most commonly known species along with T. minuta (Singh et al. 2016). Some authors place T. patula as a synonym of T. erecta, differing only in chromosome number and flower colour (FNA 1993+; FOC 1994+), while others consider them separate species (Singh et al. 2016; USDA-ARS 2024).
The achenes are generally longer (length: 8-10 mm, Singh et al. 2016) than T. minuta, with shorter, forked hairs in longitudinal rows along the angles of the achene, round glands occasional or lacking. Pappus scales are also longer with 2-4 shorter ones 2-6+ mm long and 0-2 scales much longer at 6-12+ mm (FNA 1993+; FOC 1994+). The achene end opposite the pappus is yellowish, up to ¼ of the achene length.
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Tagetes erecta
Comparison Window
Fenêtre de comparaison
MAIN SPECIES
ESPÈCES PRINCIPALES
Tagetes minuta
Tagetes minuta
Asteraceae
Tagetes minuta achenes
MAIN SPECIES
ESPÈCES PRINCIPALES
Tagetes minuta
Tagetes minuta
Asteraceae
Tagetes minuta achenes, immature
MAIN SPECIES
ESPÈCES PRINCIPALES
Tagetes minuta
Tagetes minuta
Asteraceae
Tagetes minuta achenes
MAIN SPECIES
ESPÈCES PRINCIPALES
Tagetes minuta
Tagetes minuta
Asteraceae
Tagetes minuta close up of achene
MAIN SPECIES
ESPÈCES PRINCIPALES
Tagetes minuta
Tagetes minuta
Asteraceae
Tagetes minuta achene surface with hairs and gland
MAIN SPECIES
ESPÈCES PRINCIPALES
Tagetes minuta
Tagetes minuta
Asteraceae
Tagetes minuta achene, attachment point
SIMILAR SPECIES
ESPÈCES SEMBLABLES
Tagetes erecta
Tagetes erecta
Asteraceae
Tagetes erecta achenes
SIMILAR SPECIES
ESPÈCES SEMBLABLES
Tagetes erecta
Tagetes erecta
Asteraceae
Tagetes erecta achenes
SIMILAR SPECIES
ESPÈCES SEMBLABLES
Tagetes erecta
Tagetes erecta
Asteraceae
Tagetes erecta achene
SIMILAR SPECIES
ESPÈCES SEMBLABLES
Tagetes erecta
Tagetes erecta
Asteraceae
Tagetes erecta achene surface with bifid hairs
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Reference(s)
Référence(s)
Centre for Agriculture and Bioscience International (CABI). 2024. Invasive Species Compendium, CAB International, Wallingford, UK. https://www.cabidigitallibrary.org/journal/cabicompendium. Accessed April 27, 2024.
Flora of China (FOC) 1994+. Tagetes minuta L. Vol. 20 – 21 Page 884 (English edition). http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242425855 Accessed July 18, 2024.
Flora of North America (FNA) Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 22+ vols. New York and Oxford. http://beta.floranorthamerica.org Accessed July 18, 2024.
Forsyth, C and Van Staden, J. 1983. Germination of Tagetes minuta L. I. Temperature Effects. Annals of Botany 52: 659-666.
Holm, L.G., Doll, J., Holm, E., Pancho, J.V. and Herberger, J.P. 1997. World Weeds: Natural Histories and Distribution. John Wiley & Sons, Inc. New York, NY. 1129 pp.
Integrated Taxonomic Information System (ITIS). 2024. https://www.itis.gov/ Accessed July 30, 2024.
Kaul, K. and Bedi, Y.S. 1995. Allelopathic influence of Tagetes species on, germination and seedling growth of radish (Raphanus sativus) and lettuce (Lactuca sativa). Indian Journal of Agricultural Sciences 65: 599—601.
Mukherjee, S.K. and Sarkar, A. K. 1999. Diacritical features of cypsela in Tagetes minuta L. of the tribe Tagetae (Asteraceae) with the aid of LM and SEM. Mendel International Journal 16: 9-10.
Neher, R. T. 1968. The Ethnobotany of Tagetes. Economic Botany, 22: 317-325.
Plants of the World Online (POWO). 2024. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. http://www.plantsoftheworldonline.org/ Accessed April 27, 2024.
PlantNET. 2024. The NSW Plant Information Network System. Royal Botanic Gardens and Domain Trust, Sydney. https://plantnet.rbgsyd.nsw.gov.au Accessed March 5, 2024.
Singh, P., Krishna, A., Kumar, V., Krishna S, Singh, K., Gupta, M and Singh, S. 2016. Chemistry and biology of industrial crop Tagetes species: a review. Journal of Essential Oil Research, 28: 1-14.
Singh, V., Singh, B. and Kaul, V.K. 2003. Domestication of wild marigold (Tagetes minuta L.) as a potential economic crop in western Himalaya and north Indian plains. Economic Botany 57: 535-544.
U.S. Department of Agriculture-Agricultural Research Services (USDA-ARS). 2024. Germplasm Resources Information Network (GRIN), https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch Accessed July 23, 2024.
Wang C-M., and Chen, C-H. 2006. Tagetes minuta L. (Asteraceae), a newly naturalized plant in Taiwan. Taiwania 51: 32-35.
Wang, J., Cao, K., Liu J., and Zhao, Y. 2023. Biological Characteristics and Resource Utilization of Tagetes minuta L. Journal of Resources and Ecology, 14: 533–541.
Wiersema, John, H. and Blanca León. 2016. World Economic Plants. Available from: VitalSource Bookshelf, (2nd Edition). Taylor & Francis.
World Flora Online (WFO). 2024. Available at: http://www.worldfloraonline.org Accessed April 27, 2024.