Agave rosalesii (sect. Inermes , Asparagaceae), segregated from Agave ellemeetiana K. Koch (sect. Choritepalae ): a new species from the Mixteca Alta of western Oaxaca, Mexico

Abstract

Background: Agave ellemeetiana ( A . sect. Choritepalae ) features soft and “spineless” leaves and occurs in two disjunct and ecologically differentiated populations classified as subspecies. An incidental look at the flowers of A . ellemeetiana ssp. subdentata unveiled that these did not match those of A . ellemeetiana s. str. nor those of sect. Choritepalae . Questions: Do these disjunct populations differ in flower and fruit morphology? Do they belong to the same section within Agave ? Hypotheses: The floral morphology of populations of Agave ellemeetiana ssp. subdentata from western Oaxaca places this species in A . sect. Inermes , and the set of qualitative and quantitative differences is sufficient to recognize it as a distinct species. Studied species: Agave ellemeetiana , Agave pedunculifera . Study site and dates: Putla District, western Oaxaca, December 2011 and April 2014. Methods: We conducted an alpha-taxonomic study of the Agave ellemeetiana species complex, involving two fieldwork expeditions, review of literature, online images, and herbarium specimens. Results: Differences in flower, fruit and vegetative morphology and habitat support the segregation of the populations (from the Putla District, Oaxaca) from the Agave ellemeetiana complex as a new species, A . rosalesii spec. nov. The presence of an evident corolla tube places the proposed taxon close to A . pedunculifera and within A . sect. Inermes . Conclusions: The populations from the Putla District are sufficiently distinct in their morphology and ecology to merit recognition as a new species, Agave rosalesii , placed in A . sect. Inermes . Translate stop   Translate stop