Structure and variation
Tubercles may be broad and short or distinctly elongated. They often retain a small areole near the tip. Stem colour and tubercle proportions vary among populations. Flowers are usually white or pinkish. [Anderson and Fitz Maurice 1998]
POWO accepts Ariocarpus retusus Scheidw. Its synonyms include A. furfuraceus, A. confusus and older combinations associated with the epithet elongatus. A. trigonus is treated here as a separate species, despite often appearing in older literature as a subspecies of A. retusus. [2-WWW]
Distribution and environment
The species is native to northeastern Mexico. In the regional Tamaulipas account, its sites ranged from 700 to 2100 m above sea level. The authors described rocky slopes, scrub and sites also associated with pine vegetation. This range refers to the studied part of its distribution. [2-WWW] [Martínez-Avalos and Suzán-Azpiri 2000]
In a two-year demographic study, plants sheltered by other plants had lower mortality, although such associations were relatively rare. The transition from seed to seedling proved particularly vulnerable. The finding comes from the supplied abstract and refers to the population studied. [Cárdenas-Ramos et al. 2024]
Flowering and seed production
In the seven-species comparison, mean flower width in A. retusus was the greatest, at 38.78 ± 0.82 mm. The sample comprised 38 flowers, with variation given as the standard error of the mean. A population mean is not a diagnostic feature sufficient by itself to identify every specimen. [Martínez-Peralta et al. 2014a]
Controlled pollination showed a clear advantage of other individuals' pollen. Self-pollen rarely produced fruit. Planning seed production therefore requires several distinct individuals flowering together and records of pollen provenance. [Martínez-Peralta et al. 2014b]
In Neciu's account, five-year-old plants had not yet flowered despite reaching about 5–7 cm in diameter. This description shows that size and age need assessment within a particular collection. Delayed flowering alone need not indicate disease. [Neciu 2006]
The stem surface under the microscope
A comparative epidermal study found a thick cuticle and small surface projections, with a single layer of thin-walled hypodermis beneath. The cuticle covers epidermal cells, while the hypodermis is a separate tissue layer. This distinction describes the structure more precisely than the general term “thick skin”. [Loza-Cornejo and Terrazas 2003]
Cultivation in collections
In Polish cultivation practice, adult ariocarpus plants received a predominantly mineral, permeable substrate. Watering was linked to warm growing conditions and complete drying of the pot. Repotting was careful, with as little damage as possible to the extensive roots. [Anonim 2006]
Origin from sites at different elevations and with different vegetation shelter supports observing each specimen's response. Stronger light is introduced gradually, particularly after overwintering or relocation. Small seedlings require separate care, described in the section on sowing and acclimation. [Martínez-Avalos and Suzán-Azpiri 2000] [Neciu 2006] [1-WWW]
Extracts and antimicrobial activity
Studies of this species' applications are presented in a separate account in “Biotechnology and applications”. [Rodríguez Garza et al. 2010]
Name in the ethnobotanical literature
Furst devoted a publication to A. retusus titled “Ariocarpus retusus, the ‘False Peyote’ of Huichol Tradition”. The atlas cites this historical context of the name from the publisher's bibliographic record. “Peyote” in such a title is not evidence of identical composition or effects in different plants. [Furst 1971]
Germinating pollen and pollen reaching the ovary
In plants from Miquihuana, self-pollen could germinate on the stigma, but its tubes rarely traversed the entire style. After manual self-pollination, tubes were found in the ovary of 3.8% of 26 pistils. Fruit set in a separate sample of 69 flowers was 4.3%. Growth inhibition in the style indicates where the self-incompatibility barrier acts before fertilisation. [Martínez-Peralta et al. 2014b, p. 532–536, ryc. 4, tabela 1]
In the flower morphology comparison, the studied population had the most ovules, averaging 122.6 ± 7.93 per flower in a sample of 38 flowers. Variation is the standard error. Comparing ovule number with pollen compatibility shows two components of seed production, the potential number of fertilisation sites and the ability of pollen tubes to reach them. [Martínez-Peralta et al. 2014a, p. 670, tabela 1; p. 534–536] [Martínez-Peralta et al. 2014b, p. 670, tabela 1; p. 534–536]