Abstract

ESPEJO SERNA, Adolfo  and  LOPEZ-FERRARI, Ana Rosa. Current floristic and phytogeographic knowledge of Mexican Bromeliaceae. Rev. biol. trop [online]. 1998, vol.46, n.3, pp.493-513. ISSN 0034-7744.

A current floristic and phytogeographic knowledge of native Mexican Bromeliaceae is presented. There are 22 genera of Bromeliaceae recorded from the country that include 326 species. The genus Ursulaea with 2 species is endemic to Mexico, while Hechtia with 48 of its 50 species has its principal center of diversity in the country. Tillandsia (175 spp), Hechtia (48 spp) and Pitcairnia (46 spp) are the genera with the greatest number of species. We present a comparative analysis of Mexican Bromeliaceae with that of other American regions that have recently published accounts for the Family, particularly the Mesomerican area, Venezuela, Ecuador, and the Guianas. Our results led us to the conclusion that all these floras should be considered as distinct. We observe a progressive decrease of the Simpson index value related with the remoteness of the Mexican area. A general analysis of the species numbers of Mexican bromeliad genera shows a distinct preference of the species for coniferous and oak forests, followed by tropical caducifolious forests. There is also significant representation of the family in other vegetation types such as cloud forests and tropical perennifolious forests. Generally Mexican Bromeliaceae species have scarce and sparse populations and in many cases they inhabit cliffs, bluffs and scarps in restricted areas. Concerning the geographic distribution of Mexican genera, 77.27 % are neotropical, 4.54% are South American and the remainder are Mexican and Central American. The generic endemism is very low (4.54 %), even if we extend the country limits to Megamexico sensu Rzedowsi (1991) it reaches only 13.63 %. The family endemism at specific level reaches 63.07 %. There are not available data about a specific analysis of the conservation status of Mexican Bromeliaceae, but we can point out that a great number of taxa are only known from the type collection or at the most from the type locality. This can perhaps be attributed in part to the fact that there is a lack of sufficient collections; however, we suppose that several species are surely endangered.

Keywords : Bromeliaceae; Mexico; Megamexico; Mesoamerica; Neotropic; floristics; phytogeography.