A Synopsis of <em>Croton</em> (Euphorbiaceae) in Michoacán, Mexico

Abstract

A taxonomic and nomenclatural review of the genus Croton (Euphorbiaceae) in the Mexican state of Michoacán is presented. Six sections and 20 species are here reported. The greatest diversity is in the Balsas Depression province, where at least 12 species occur. There is a strong tendency to thrive in tropical deciduous forest. An identification key is provided, and for each species, the following information is included: protologue citation, type information, habit, habitat, and elevation within the state, regional and global distribution, and phenology. Relevant synonyms are listed, as too are herbarium specimens. Lectotypes are designated for Croton draco, C. niveus, and C. calvescens. One species, Croton rojasii, is described as new and illustrated with photos. It is known only from tropical deciduous forest in the Zicuirán-Infiernillo Biosphere Reserve, at elevations from 400 to 700 m. It belongs to sect. Geiseleria and is remarkable because of the strongly unequal pistillate sepals, the larger of which becoming accrescent and exceeding the fruit.

Keywords

• Balsas Depression
• new species
• Pacific Lowlands
• sect. <i>Geiseleria</i>
• Sierra Madre del Sur
• Trans-Mexican Volcanic Belt