The genus Manfreda (Asparagaceae; Agavoideae) in Guerrero, Mexico: richness, distribution and the description of a new species

Abstract

Background: Manfreda includes 37 species distributed from southeastern United States to Honduras. The Pacific Lowlands and Sierra Madre del Sur biogeographic provinces and Guerrero state are the centers of species richness and endemism for the genus in Mexico.
 Questions: How is the geographical distribution of Manfreda in Guerrero? Some specimen does not match any known Manfreda species, could be these collections a new species?
 Studied species: Fourteen Manfreda species.
 Study site: Guerrero, Mexico.
 Methods: The analysis was based on specimens reviewed from 19 herbaria, fieldwork, and records in specialized literature. The richness was quantified by municipalities, biogeographic provinces, and a grid cell, using geographic information systems. The morphological descriptions and the recognition of new species are based on traditional taxonomic methods.
 Results: Database included 86 records for 14 species. The richness is concentrated in 10 cells located in the transition between the Balsas Basin, Transmexican Volcanic Belt and the Sierra Madre del Sur. Some specimens that could not be assigned to any of the known species in Manfreda and proposed as a new species, which is presented with illustrations, an identification key, and a distribution map.
 Conclusions: Given the richness, the endemism, and the low density of collections of Manfreda in Guerrero, we found that the richness is likely greater than previously estimated and it could be expected to find new species. It is advisable to focus on the collection towards the Pacific Lowlands, since there is the greatest richness in Mexico.