History of Genus - Description of Genus - Division of Genus - Taxonomy and Morphology
History of Genus
The separate genus Acharagma was created by Charles Glass in 1998 from the original section of Acharagma of the genus Escobaria. N. P. Taylor (1983)
transferred to this section two taxa that were very difficult to classify into the Cactaceae family, E. roseana and E. aguirreana. Both have
undergone many taxonomic changes during their history and have traveled gradually among the genera Echinocactus, Neolloydia, Coryphantha,
Gymnocactus, Thelocactus and Escobaria. Taxon roseanum was originally described by Bödeker in 1928 as a representative of the genus Echinocactus,
but over the years it has settled for a long time only in the genus Escobaria. In 1970, he was transferred by Glass and Foster to the genus Gymnocactus,
which later included the newly discovered species G. aguirreanus (Glass et Foster 1972). However, as early as 1978, Anderson and Ralston considered that both
taxa should be included in the genus Turbinicarpus due to their different morphological features or that a separate genus should be created for them.
According to John and Øíha (1981a, 1981b), the taxa roseanus and aguirreanus do not correspond to the characteristics of the genus Gymnocactus
due to their soft body, elastic thorns and cylindrical fleshy fruits. The well-seeded seed test, on the other hand, suggests a connection with the genera Mammillaria
and Escobaria, but the classification of these genera contradicts the construction of the nipples. They lack an axilla or furrow on the nipple. They considered
that the absence of a furrow, although an important characteristic, was not so important that a separate genus should be established for both species. They argued that
the absence of a wart on the nipple could be questionable even within one species, with reference to Ortegocactus macdougallii, and they included both taxa
in the subgenus Primibaria in their division of the genus Escobaria.
In 1983, N. P. Taylor revised the genus Escobaria and placed the taxa G. roseanus and G. aguirreanus in the newly created Acharagma section. The reason for the creation of the new section was mainly the different place of flower formation outside the axillary areola or furrow. When comparing fruits, seeds and epidermis, it was also found that their characteristics do not include these species in the genus Thelocactus and Gymnocactus. Just before his death, Ch. Glass (1998) Taylor's Acharagma section on a separate genus with reference to earlier studies by A. D. Zimmerman (1985). However, it was no longer enough to process a detailed description of one's own genus or to transfer both species already known at that time to this genus. This was not completed by E. F. Anderson in his book The Cactus Family from 2001. Since about 1995, botanists' attention has been focused on the study of plants using molecular analyzes such as DNA analysis or "rpl16 intron" analysis. In combination with phylogenetic studies of selected taxa of the Cactaceae family, new cladistic connections are discovered and specified. Based on the results of studies conducted by E. F Anderson (2001), Butterworth, Cota-Sanches and Wallace (2002), Crozier (2005), Hernández-Hernández et al. (2011), Vázquez-Sánchez et al. (2013 and 2019) it can be stated that the emergence of a separate genus Acharagma is fully justified in terms of taxonomic inclusion and the genus as such has the closest links to the genera Rapicactus (created from some members of the genus Turbinicarpus), Obregonia and Lophophora.
The history of the genus can be concluded for the time being with the newly described taxon A. huasteca, the description of which was published by Z. Elhart in 2011.
In 2021, it was informed about the ongoing study of some taxa from the A. roseanum circle, which will probably result in the description of two other subspecies in the future. In the work of Mynar and Nitzschke (2021), they were preliminarily referred to as A. roseanum subsp. menzeliorum ined. and A. roseanum subsp. rudolphiorum ined.
Translation - Google Translator.
Description of Genus
The original description (1998)
Acharagma (Taylor) Ch.Glass, Guía Identific. Cact. Amenazadas México, 1: Ac/ag, 1998, pub. 1997
Escobaria sect. Acharagma Taylor sect. nov., Kakteen und andere Sukkulenten, 34: 185, 1983
The others descriptions of the genus
Acharagma (Taylor) Ch. Glass
E. F. Anderson, The Cactus Family, p.108, Timber Press Portland, Oregon, 2001
Acharagma (Taylor) Ch. Glass
D.R.Hunt, N.P.Taylor, G.Charles, The New Cactus Lexicon, p.26, DH Books, 2006