Homalocephala (plant)
| Homalocephala | |
|---|---|
| Homalocephala polycephala | |
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Caryophyllales |
| Family: | Cactaceae |
| Subfamily: | Cactoideae |
| Tribe: | Cacteae |
| Genus: | Homalocephala Britton & Rose[1] |
| Type species | |
| Homalocephala texensis | |
| Species | |
|
See text. | |
Homalocephala is a genus of plants native to Mexico and the United States.[1]
Description
Plants in this genus differ from Echinocactus and Astrophytum by having stem that have few trichomes at the apex and acute ribs; flowers that are slightly tubular rather than campanulate; embryos that are campilotropous and acute cotyledons.[2]
Taxonomy
In the past, all three species have been considered to be in the genus Echinocactus. In 1922 by Nathaniel Lord Britton and Joseph Nelson Rose segregated E. texensis to its own genus Homalocephala based on differences in growth form and fruit morphology. Homalocephala was then moved to a subgenus of Echinocactus by Alwin Berger in 1929. The subgenus was elevated to a genus again in 2018 based on morphological and molecular evidence.[2]
Species
As of June 2025, Plants of the World Online accepts three species:
| Image | Scientific name | Common name | Distribution |
|---|---|---|---|
| Homalocephala parryi (Engelm.) Vargas & Bárcenas syn. Echinocactus parryi |
Devil's cushion | Mexico | |
| Homalocephala polycephala (Engelm. & J.M.Bigelow) Vargas & Bárcenas syn. Echinocactus polycephalus |
Cotton top cactus | S. California, S. Nevada, Arizona, Mexico | |
| Homalocephala texensis (Hopffer) Britton & Rose syn. Echinocactus texensis |
Horse crippler cactus | SW. Oklahoma to NE. Mexico |
References
- ^ a b "Homalocephala Britton & Rose | Plants of the World Online | Kew Science". Plants of the World Online. Retrieved 2025-06-07.
- ^ a b Vargas-Luna, Mario Daniel; Hernández-Ledesma, Patricia; Majure, Lucas Charles; Puente-Martínez, Raúl; Macías, Héctor Manuel Hernández; Luna, Rolando Tenoch Bárcenas (2018-11-13). "Splitting Echinocactus: morphological and molecular evidence support the recognition of Homalocephala as a distinct genus in the Cacteae". PhytoKeys (111): 31–59. Bibcode:2018PhytK.111...31V. doi:10.3897/phytokeys.111.26856. ISSN 1314-2003. PMC 6246732. PMID 30483031.
- Innes C, Wall B (1995). Cacti, Succulents and Bromeliads. Cassell & The Royal Horticultural Society.
External links
- Media related to Homalocephala at Wikimedia Commons
- Data related to Homalocephala (plant) at Wikispecies
- Jepson Manual Treatment: Echinocactus
- Cactus-mall.com: "Lost Peyotls"