Echinocactus
Echinocactus, Verh. Vereins. Beförd. Gartenbaues Königl. Preuss. Staaten 3: 420. 1827 sec. Vargas-Luna & al. 20181
- 1. Vargas-Luna, M.D., Hernández-Ledesma, P., Majure, L.C., Puente-Martínez, R., Hernández Macías, H.M. & Bárcenas Luna, R.T. 2018: Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae. – PhytoKeys 111. http://doi.org/10.3897/phytokeys.111.26856
- =Echinofossulocactus in Gard. Mag. & Reg. Rural Domest. Improv. 17: 317. 1841 syn. sec. Vargas-Luna & al. 20182
- 2. Vargas-Luna, M.D., Hernández-Ledesma, P., Majure, L.C., Puente-Martínez, R., Hernández Macías, H.M. & Bárcenas Luna, R.T. 2018: Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae. – PhytoKeys 111. http://doi.org/10.3897/phytokeys.111.26856
- =Brittonrosea in Anales Soc. Ci. Argent. 96: 69. 1923 syn. sec. Vargas-Luna & al. 20183
- 3. Vargas-Luna, M.D., Hernández-Ledesma, P., Majure, L.C., Puente-Martínez, R., Hernández Macías, H.M. & Bárcenas Luna, R.T. 2018: Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae. – PhytoKeys 111. http://doi.org/10.3897/phytokeys.111.26856
- =Emorycactus in Succulenta (Netherlands) 75: 270. 1996 syn. sec. Vargas-Luna & al. 20184
- Type: Emorycactus polycephalus
- 4. Vargas-Luna, M.D., Hernández-Ledesma, P., Majure, L.C., Puente-Martínez, R., Hernández Macías, H.M. & Bárcenas Luna, R.T. 2018: Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae. – PhytoKeys 111. http://doi.org/10.3897/phytokeys.111.26856
- =Meyerocactus in Succulenta (Netherlands) 75: 271. 1996 syn. sec. Vargas-Luna & al. 20185
- 5. Vargas-Luna, M.D., Hernández-Ledesma, P., Majure, L.C., Puente-Martínez, R., Hernández Macías, H.M. & Bárcenas Luna, R.T. 2018: Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae. – PhytoKeys 111. http://doi.org/10.3897/phytokeys.111.26856
Notes
Echinocactus turns out to be paraphyletic in recent molecular studies (Bárcenas & al. 2011; Hernández-Hernández & al. 2011; Vázquez-Sánchez & al. 2013), with E. grusonii Hildm. resolved in a separate clade from the remaining four species. Vargas-Luna & al. (2018) showed that Echinocactus s.l. was paraphyletic with Astrophytum nested within, and E. grusonii resolved as sister to Ferocactus. They re-circumscribed Echinocactus to reflect this well-supported topology and also showed morphological characters to recognize two genera, Echinocactus s.s., and Homalocephala. It is clear that the monotypic Kroenleinia grusonii is not a member of Echinocactus, however, its distinction from Ferocactus is not entirely clear. See Kroenleinia.A,B,C,D,E
Taxon standing
Category B. The genus is monophyletic based on phylogenetic studies that support the clade based on a sufficiently dense or even complete sampling, or support a monotypic genus as a distinct lineage, but do not provide a new taxonomic treatment at the species level. In many cases, older classical taxonomic synopses or a monographic treatment exist for these genera providing a reliable assessment of the species included.
Bibliography
A. Bárcenas, R.T., Yesson, C. & Hawkins, J. A. 2011: Molecular systematics of the Cactaceae. – Cladistics 27: 1-20. http://doi.org/10.1111/j.1096-0031.2011.00350.x
B. Hernández-Hernández, T., Hernández, H.M., De-Nova, J. A., Puente, R., Eguiarte, L.E. & Magallón, S. 2011: Phylogenetic relationships and evolution of growth form in Cactaceae (Caryophyllales, Eudicotyledoneae). – American Journal of Botany 98(1): 44-61. http://doi.org/10.3732/ajb.1000129
C. Majure, L.C. 2021: Revisions of Cochemiea, Consolea, Coryphantha, Cylindropuntia, Cumarinia, Grusonia, Kroenleinia, Leptocereus, Melocactus, Micropuntia, Opuntia. – In: Korotkova N. & al., Cactaceae at Caryophyllales.org – a dynamic online species-level taxonomic backbone for the family. – Willdenowia 51: 251-270. http://doi.org/10.3372/wi.51.51208
D. Vargas-Luna, M.D., Hernández-Ledesma, P., Majure, L.C., Puente-Martínez, R., Hernández Macías, H.M. & Bárcenas Luna, R.T. 2018: Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae. – PhytoKeys 111. http://doi.org/10.3897/phytokeys.111.26856
E. Vázquez-Sánchez, Terrazas, T., Arias, S. & Ochoterena, H. 2013: Molecular phylogeny, origin and taxonomic implications of the tribe Cacteae (Cactaceae). – Systematics and Biodiversity 11(1): 103-116. http://doi.org/10.1080/14772000.2013.775191