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Arbutus mollis Kunth in H.B.K. treated since long ago as a synonym of A. xalapensis Kunth in H.B.K. is the correct name for the plants formerly treated as A. occidentalis var. villosa McVaugh & Rosatti. A revision of the complex of A. occidentalis McVaugh & Rosatti reveals that the two varieties originally described for that species differ in characters of foliage, indument and inflorescence, which suggests an origin from different lineages and justify their separation to the species level, and therefore A. mollis is recognized here as an independent species. The shrubby habit shared by A. mollis and A. occidentalis is probably a case of convergent evolution. The taxonomic reinstatement of A. mollis is made and amended descriptions for A. mollis and A. occidentalis and a key to distinguish them are given. Apparent intermediates are either morphs, hybrids, stump sprouts of tree species after fire or cutting, or rarely shrubby forms of other species. The following hybrids are documented: Arbutus mollis x A. tessellata (Guanajuato and Michoacán), Arbutus mollis x A. xalapensis (Querétaro), Arbutus occidentalis x A. arizonica (Durango, Aguascalientes, and Jalisco), Arbutus occidentalis x A. tessellata (Jalisco), Arbutus occidentalis x Arbutus bicolor (Chihuahua and Durango), and Arbutus occidentalis x Arbutus aff. xalapensis (Durango and Jalisco). [ABSTRACT FROM AUTHOR]

Arbutus bicolor S. González, M. González et P. D. Sørensen, sp. nov. is described and illustrated. It is related to A. xalapensis H.B.K. and has been generally misidentified as A. glandulosa M. Martens & Galeotti, a synonym of the latter name. The new species is distinguished by having densely glandular pubescent branchlets and petioles; markedly bicolored leaves that are whitish to pale ochroleucous below due to a dense and uniform indument of tightly curled hairs, leaves red at senescence; and pink, rarely white flowers. Arbutus bicolor is widely distributed in the Sierra Madre Occidental and the Transvolcanic Belt and reaches the western slopes of the Sierra Madre Oriental in central Mexico. Sporadic hybridization occurs with A. madrensis S. González, A. occidentalis McVaugh & Rosatti, A. tessellata Sørensen, and A. xalapensis. A key to distinguish A. bicolor from other Mexican tree species of Arbutus is provided. [ABSTRACT FROM AUTHOR]