The genus Neobuxbaumia brings together tall, often tree-like columnar cacti of Mexico, which dominate the semi-arid landscapes of the east and south of the country, notably the Tehuacán-Cuicatlán valley. These columnar cacti of the Cactaceae family were set apart as a genus in 1938 and merged into Cephalocereus in 2017. Plants of the World Online (POWO), the reference database of the Royal Botanic Gardens, Kew, no longer recognises Neobuxbaumia: botanically, its species now carry the name Cephalocereus, so Neobuxbaumia polylopha becomes Cephalocereus polylophus. The name Neobuxbaumia is still the one under which these plants are sold and searched for, and Succulentes keeps it as a working name. The species most often grown is Neobuxbaumia polylopha, a regular green column that can exceed ten metres in the wild.
Key facts
- Status (POWO): Neobuxbaumia Backeb. (1938) is a synonym of Cephalocereus Pfeiff.; the name is kept here as a working name
- Number of species: 8 or 9 depending on the author before the merger; POWO now places all of them in Cephalocereus, which has 13 accepted species
- Family: Cactaceae, subfamily Cactoideae
- Common names: no English name for the genus; “tetecho” in Mexico for Neobuxbaumia tetetzo; “cone cactus” or “golden saguaro” for Neobuxbaumia polylopha
- Natural range: eastern and southern Mexico
- CITES: Appendix II, as for almost all Cactaceae
Taxonomy: the merger with Cephalocereus
The change comes from a 2017 study by Tapia, Bárcenas-Argüello, Terrazas and Arias in Systematic Botany. Combining molecular and morphological data, the authors showed that Neobuxbaumia was not a natural group: it appeared paraphyletic, because Cephalocereus was itself polyphyletic and the small genus Pseudomitrocereus was nested inside it. They therefore united the species of the three genera under the oldest name, Cephalocereus. POWO follows this treatment. The genus was created in 1938 by Curt Backeberg and honours Franz Buxbaum (1900-1979), an Austrian cactus botanist; the prefix “Neo-” was added because Buxbaumia was already a genus of mosses.
Species
- Neobuxbaumia euphorbioides (Cephalocereus euphorbioides): Tamaulipas and Veracruz.
- Neobuxbaumia laui (Cephalocereus novus): Oaxaca.
- Neobuxbaumia macrocephala (Cephalocereus macrocephalus): Puebla and Oaxaca; protected in Mexico.
- Neobuxbaumia mezcalaensis (Cephalocereus mezcalaensis): western to southern Mexico, the widest range of the group.
- Neobuxbaumia polylopha (Cephalocereus polylophus): Guanajuato, Hidalgo, Querétaro, San Luis Potosí; the most widely grown species.
- Neobuxbaumia scoparia (Cephalocereus scoparius) and Neobuxbaumia squamulosa (Cephalocereus nudus): Mexico.
- Neobuxbaumia tetetzo (Cephalocereus tetetzo): Tehuacán-Cuicatlán valley, pollinated by bats.
Cultivation and conservation
These cacti are grown like other large Mexican columnar species: plenty of light (light shade for young plants, full sun later), a fast-draining mineral substrate, and a dry winter. They stay small for a long time in pots, which makes them collection and conservatory plants rather than garden plants outside the mildest climates. Propagation is by seed. In the wild, Neobuxbaumia tetetzo is pollinated by nectar-feeding bats, and its seedlings survive mostly in the shade of nurse shrubs. All species are in CITES Appendix II; Neobuxbaumia polylopha is listed as Vulnerable by the IUCN. Plants on the European market come from seed.
Reference sites
- Plants of the World Online (POWO), Cephalocereus polylophus: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:52188-2
- Tapia, H.J., Bárcenas-Argüello, M.L., Terrazas, T. & Arias, S. (2017). Phylogeny and circumscription of Cephalocereus (Cactaceae) based on molecular and morphological evidence. Systematic Botany 42(4): 709–723.