Orchids from the municipalities of Santo Domingo Yanhuitlan and San Pedro y San Pablo Teposcolula, Oaxaca.

Abstract

In Oaxaca the Mixteca Alta region is characterized by its high rates of marginalization, edaphic erosion, and deforestation; but also, because its floristic diversity is known only by some isolated studies and at present there are still areas whose floristic richness had not been documented. Here is present an orchideological inventory of a portion of the Mixteca Alta that has been scarcely explored botanically, which correspond to the municipalities of Santo Domingo Yanhuitlán and San Pedro y San Pablo Teposcolula. Both municipalities are part of Cerros Negro-Yucaño priority terrestrial region and the floristic province of the Tehuacan-Cuicatlan valley, so this study contributes to the knowledge of the biodiversity of both regions. This inventory was based on field work, review of herbarium collections, and literature. Fifty-six species (six of them represented by infraspecific categories) and 26 genera of orchids are reported; most (83.9 %) are of terrestrial/rupicolous habit; twenty are endemic to Mexico, and four are restricted to the limits of Oaxaca. Malaxis reichei and Habenaria macvaughiana are new reports for the flora of Oaxaca; Bletia lilacina, Bletia urbana, Habenaria guadalajarana, and Platanthera brevifolia are new records for the flora of the Tehuacan-Cuicatlan valley. Four species are protected by Mexican laws; Laelia albida, Laelia furfuracea, and Prosthechea karwinskii have ornamental and commercial value, they present abundant populations in the study zone, although in other areas of Oaxaca they face risks due to the extraction for local trade and religious uses.