Dugesia mexicana
| Dugesia mexicana | |
|---|---|
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| Dugesia mexicana | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Subfamily: | Asteroideae |
| Tribe: | Heliantheae |
| Subtribe: | Dugesiinae Panero |
| Genus: | Dugesia A.Gray |
| Species: | D. mexicana |
| Binomial name | |
| Dugesia mexicana | |
| Synonyms | |
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Dugesia mexicana, with no English name, is the only species in the plant genus Dugesia, which should not be confused with the flatworm genus Dugesia. Native only to Mexico, Dugesia mexicana belongs to the vast Aster, Composite or Sunflower Family, the Asteraceae.
Description
An enormous number of yellow-flowered members of the huge Aster Family exist. However, as might be expected of the single species in a monotypic genus, Dugesia mexicana exhibits a unique combination of features. Here are the key ones:
- It is an herbaceous plant which can become perennial. Its stems, only up to 30 cm (12 in) long, lie close to the ground or ascend, and form dense,circular mats. Vegetative parts are variously hairy, sometimes densely so.
- Principle leaves concentrate at the base forming rosettes. They have petioles up to 8 cm (3+1⁄4 in) long and deeply pinnately or twice-pinnately lobed blades up to 12 cm (4+1⁄2 in) long and 5 cm (2 in) broad. Stem leaves are smaller than basal ones.
- Floral heads arise at stem tips or where leaves attach to their stem, on peduncles up to 8 cm (3 in) long. At the floral head's base there are 5 broad, leafy bracts up to 12 mm (1⁄2 in) long. Above these broad bracts there are smaller bracts about half the length and much narrower, and of the same number, 8-13, as the flat, petal-like "ray florets." The ray florets' yellow corollas, up to 12 mm (1⁄2 in) long, are deeply notched at their tips and display conspicuous brown to black nerves. The floral head's "eye" consists of 60-80 "disc florets" with cylindrical, yellow corollas. Ray flowers produce fruits, but disc florets are sterile.
- The browish, one-seeded, cypsela-type fruits commonly are broadest above their middles, flattened, their sides bearing remarkable "wings" divided into as many as 6 more or less semicircular segments diminishing in size toward the cypsela's base. Unlike most Aster Family species, cypselae in Dugesia mexicana develop no pappuses.
Distribution
Dugesia mexicana is endemic just to the south-central Mexican states of Hidalgo, México, Michoacán, Puebla, Querétro, San Luis Potosí, Tlaxcala and Veracruz.
Habitat
Dugesia mexicana often appears along roadsides and in open, grassy areas at elevations of 2,000–2,550 m (6,560–8,370 ft) above sea level.
Ecology
In the Mexican state of Hidalgo, Dugesia mexicana is utilized by butterflies.
Phenology
Dugesia mexicana flowers and fruits in September. Images on this page show an individual flowering in late August.
As traditional medicine
In Mexico's Hidalgo state, Dugesia mexicana -- known locally as hierba del puerco, translatable to "pigweed"-- is used to treat diarrhea of babies when their teeth are emerging, also for tooth pain in general, for stomach ache and dolor de riñones, which in this area refers to low back pain.
Taxonomy
In 1882 when Asa Gray formally described and named Dugesia mexicana, at the same time he erected the genus Dugesia, in which today it remains the sole species.
Phylogeny
A phylogenetic analysis using DNA sequencing data involving internal transcribed spacers and external transcribed spacers indicated that among the six genera of the subtribe Engelmanniinae of the tribe Heliantheae, and five genera closely related to the Engelmanniinae, the genus Dugesia appeared to be "... a paleoendemic relict isolated in the mountains of Mexico." Thus apparently Dugesia mexicana is a species that formerly was widespread but now is restricted to a smaller area, a mountainous refugium. Climate change is thought to be the driving force in evolving such species, generally involving habitat loss.
Moreover, the genus Dugesia was found to be sister to the similarly monotypic genus Rojasianthe of southern Mexico and Guatemala. These two genera were the most basal genera of the subtribe Engelmanniinae.
Etymology
The genus name Dugesia honors Alfredo Dugès, a zoologist in the Mexican state of Guanajuato, who supplied plant specimens from central Mexico to Asa Gray, who formally named and described the genus.
The species name mexicana refers to Mexico, its only native home.
References
- 1 2 "Dugesia mexicana A.Gray". Plants of the World Online. United Kingdom: Royal Botanic Gardens Kew. 2026. Retrieved October 16, 2026.
- 1 2 3 Rzedowski, Jerzy; Calderón de Rzedowski, Graciela (September 2008). "Crassulaceae" (PDF). Flora del Bajío y de Regiones Adyacentes (in Spanish). 157. Pátzcuaro, Michoacán, México: Instituto de Ecología, A.C. (INECOL): 217–220. Retrieved October 16, 2026.
- ↑ Villaseñor, José Luis (August 4, 2016). "Checklist of the native vascular plants of Mexico". Revista Mexicana de Biodiversidad. 87. Mexico City, Mexico: Universidad Nacional Autónoma de México. Retrieved October 16, 2026.
- ↑ Hanan Alipi, Ana María; Mondragón Pichardo, Juana (July 10, 2009). Vibrans, Heike (ed.). "Dugesia mexicana (A. Gray) A. GrayHierba amargosa". Malezas de México (in Spanish). Mexico. Retrieved October 16, 2026.
- ↑ Beteta Hernánez, Claudia Itzel (December 2018). Redes de interacciones entre mariposas y plantas en un gradiente de urbanización en el área metropolitana de Pachuca, Hidalgo, México (PDF). uaeh.edu.mx (Maestra en Ciencias thesis) (in Spanish). Mineral de La Reforma, Hidalgo, Mexico: Universidad Autónoma del Estado de Hidalgo. Retrieved October 16, 2026.
- ↑ "Dugesia mexicana Research Grade". iNaturalist. August 30, 2023. Retrieved October 16, 2026.
- ↑ Molina-Mendoza, José Luis; Galván-Villanueva, Raquel; Patiño-Siciliano, Alfredo; Fernández-Nava, Rafael (August 2012). "Plantas medicinales y listado florístico preliminar del municipio de Huasca de Ocampo, Hidalgo, Méxcio" (PDF). Polibotánica (in Spanish with English abstract). 34. México, DF, México: Instituto Politécnico Nacional: 239–271. ISSN 1405-2768.
{{cite journal}}: CS1 maint: unrecognized language (link) - ↑ "Dolor de riñón". Atlas de las Plantas de la Medicina Tradicional Mexicana (in Spanish). Mexico City, Mexico: Universidad Nacional Autónoma de México. 2009. Retrieved October 16, 2026.
- 1 2 Gray, Asa (1882). "Contributions to North American Botany". Proceedings of the American Academy of Arts and Sciences. Vol. 17. Boston, MA, USA: John Wilson & Son. p. 216. Retrieved October 16, 2026.
- 1 2 Clevinger, Jennifer A.; Panero, Jose L. (2000). "Phylogenetic Analysis of Silphium and Subtribe Engelmanniinae (Asteraceae: Heliantheae) based on ITS and ETS Sequence Data". American Journal of Botany. 87 (4). Botanical Society of America: 565–572. Retrieved October 17, 2026.
- ↑ Harrison, Susan; Noss, Reed (February 22, 2017). "Endemism hotspots are linked to stable climatic refugia". Annals of Botany. 119 (2). United Kingdom: Oxford University Press: 207–214. doi:10.1093/aob/mcw248. Retrieved October 17, 2026.