Aztekium
| Aztekium | |
|---|---|
| File:Aztekium ritteri.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Cacteae |
| SubTribe | |
| Genus | Aztekium |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015). |
Etymology
The genus was named Aztekium because the unique relief on its ribs reminded the author (Boedeker) of Aztec sculptures and architectural patterns.
Description
Aztekium is a genus consisting of small to medium-sized plants, which can be solitary or caespitose (forming clumps). They are globose in shape, often depressed at the apex, with a characteristic greyish-green epidermis. The ribs are wrinkled and transversally streaked. Spines are weak and deciduous, often falling off as the plant matures.
The flowers are diurnal and emerge from the apex. Their colors range from pinkish-white to intense pink or magenta. They are pollinated by small insects. The fruits are relatively small, dry when ripe, and hidden within the apical wool; they exhibit irregular dehiscence. The seeds are brown to black, tuberculate, and feature a strophiole near the hilum. Seed dispersal is myrmecophilous (carried out by ants).
Habitat
Aztekiums are found in extremely localized habitats in Mexico, growing at altitudes between 600 m and 1200 m.
- A. ritteri and A. valdezii typically grow in the shade on ravines and steep slopes of weathered slate.
- A. hintonii prefers full sun on gypsum cliffs and hills, often growing alongside Geohintonia mexicana.
Distribution
- Mexico (Nuevo León)
Species
According to the Joël Lodé index, the genus currently includes 3 recognized species:
Notes
- For a long time, the genus was considered monospecific (containing only A. ritteri) until the discovery of A. hintonii in the 1990s and A. valdezii in 2010.
- Molecular data (Butterworth et al., 2002; Hernández-Hernández et al., 2011) confirms that Aztekium is a monophyletic genus and belongs to the same clade as Geohintonia.
- There is significant debate regarding the origins of some species. One theory suggests that Geohintonia mexicana might be a stabilized natural hybrid between Aztekium hintonii and possibly Echinocactus horizonthalonius.
- Another theory by Roy Mottram suggests that A. hintonii itself could be a stabilized hybrid between Geohintonia mexicana and A. ritteri.
- Despite historical morphological comparisons, DNA studies show no direct parental relationship between Aztekium and Strombocactus.
