Taxonomic Revision of Pseudognaphalium (Asteraceae, Gnaphalieae) from North America
The genus Pseudognaphalium Kirp., segregated from Gnaphalium L., is one of the largest genera of the tribe Gnaphalieae (Asteraceae) with about 60 species, most of them found in South, Central, and North America, but some species also occurring in Africa, Asia, Europe, and New Zealand. We present a taxonomic revision of Pseudognaphalium for North America accepting 36 species, mainly distributed in the Nearctic Region and the Mexican Transition Zone, and about one third of the species occurring in the Neotropical Region. The following taxa are newly synonymized: G. oaxacanum Greenm. with P. semiamplexicaule (DC.) Anderb., G. schraderi DC. with P. attenuatum (DC.) Anderb. var. sylvicola (McVaugh) Hinojosa & Villaseñor, P. altamiranum (Greenm.) Anderb. with P. roseum (Kunth) Anderb., and P. beneolens (Davidson) Anderb. with P. thermale (E. E. Nelson) G. L. Nesom. Lectotypes are newly designated for G. oblanceolatum Greenm., G. panniforme S. F. Blake, G. ramosissimum Nutt., G. roseum Kunth var. angustifolium Benth., G. roseum var. hololeucum Benth., and G. roseum var. sordescens Benth. Morphological descriptions are provided as well as taxonomic data on nomenclatural types, including synonymies, illustrations, distribution maps, distribution and habitat, additional material examined, distinguishing characters and taxonomic affinities for each taxon, biogeographical and ecological comments, and a key for their identification.