Lophocereus

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Lophocereus

Lophocereus (A.Berger) Britton & Rose in Contr. U.S. Natl. Herb. 12: 426. 1909 sec. Arias & al. 20121
  • Cereus subg. Lophocereus A.Berger in Rep. (Annual) Missouri Bot. Gard. 16: 62. 1905 syn. sec. Arias & al. 20121
  • Pachycereus sect. Lophocereus (A.Berger) P.V.Heath in Calyx 2: 106. 1992 syn. sec. Arias & al. 20121
  • 1. Arias, S., Gama López, S., Guzmán Cruz, L. U. & Vázquez-Benítez, B. 2012: Cactaceae. – In: Medina, L. R., Flora del Valle de Tehuacán-Cuicatlán 95. – México D. F.: Instituto de Biología, Universidad Nacional Autónoma de México
  • 2. Arias, S., Gama López, S., Guzmán Cruz, L. U. & Vázquez-Benítez, B. 2012: Cactaceae. – In: Medina, L. R., Flora del Valle de Tehuacán-Cuicatlán 95. – México D. F.: Instituto de Biología, Universidad Nacional Autónoma de México

Notes

Phylogenetics: Lophocereus (including L. gates and L. schottii) was strongly recognized as a separate genus, restricted to the Sonoran Desert, by e.g. Lindsay (1963) and Bravo-Hollis (1978). Comparative studies carried out by Gibson & Horak (1978) showed that those species share morphological and anatomical characteristics with Pachycereus marginatus. However, other taxonomists preferred to include this genus and others (e.g. Backebergia, Lemaireocereus, Marginatocereus, Mitrocereus, Pterocereus) in a broader genus Pachycereus (Barthlott & Hunt 1993; Hunt 2006). Phylogenetic studies based on structural (anatomy + morphology) and molecular data confirm that Lophocereus is monophyletic including three species (L. marginatus as sister to the remaining species). The genus represents a lineage within the subtribe Pachycereinae but is not directly related to Pachycereus s.str. or Backebergia (Hartmann & al. 2001, 2002; Arias & al. 2003; Arias & Terrazas 2006). A proposal to recognize this genus newly circumscribed (now going also beyond the Sonoran Desert) was conducted by Arias & al. (2012).
Lophocereus now includes taxa characterized by cylindrical stems with basal branching, an apical fertile zone with areoles, and spines larger than those of the sterile zone, and two or more flowers per areole. The flowering zone is conspicuously modified in all three species, although in L. gatesii and L. schottii internodes are shorter and spines are longer (Arias & Terrazas 2009; Arias & al. 2012). Structural changes in the fertile zone exist between several genera of Pachycereinae, including cephalium (e.g. Backebergia, Cephalocereus spp.), pseudocephalium (e.g. Lophocereus, Neobuxbaumia spp.) and intermediate forms. However, those structures are highly homoplastic and occur within several genera.A

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. Hernández-Ledesma, P., Berendsohn, W. G., Borsch, T., von Mering, S., Akhani, H., Arias, S., Castañeda-Noa, I., Eggli, U., Eriksson, R., Flores-Olvera, H., Fuentes-Bazan, S., Kadereit, G., Klak, C., Korotkova, N., Nyffeler, R., Ocampo, G. & Ochoterena, H. 2015: A taxonomic backbone for the global synthesis of species diversity in the angiosperm order Caryophyllales. – Willdenowia 45(3): 281-383. http://doi.org/10.3372/wi.45.45301