Morphometric Analysis and Synopsis of Pseudognaphalium (Gnaphalieae, Asteraceae) in North America

Pseudognaphalium Kirp. (Asteraceae, Gnaphalieae) consist of about 60 species mainly distributed in South, Central, and North America. As a first contribution toward a comprehensive taxonomic review of Pseudognaphalium, we perform here the first morphometric analysis of North American species, using UPGMA method for the construction of the dendrogram. Based upon these results we present a synopsis including a key to identify species and their associated synonymy. Thirty-seven species are recognized, two taxa are newly synonymized, Pseudognaphalium microcephalum under the name P. canescens and Pseudognaphalium semilanatum under the name P. semiamplexicaule, and two other names are confirmed as synonyms as previously proposed, Pseudognaphalium micradenium as a synonym of P. helleri and Pseudognaphalium crenatum as a synonym of P. viscosum. Lectotypes are newly designated for Gnaphalium beneolens, G. berlandieri (= Pseudognaphalium stramineum), Gnaphalium decurrens (= Pseudognaphalium macounii), G. leucocephalum, G. oxyphyllum, G. oxyphyllum var. semilanatum (= P. semiamplexicaule), G. semiamplexicaule, G. sulphurescens (= P. stramineum), G. thermale, and second-step lectotypifications are proposed for G. helleri and G. wrightii (= P. canescens). In addition, the first illustrations of Pseudognaphalium helleri and P. semiamplexicaule, and a colour figure of P. canescens and P. beneolens emphasizing the results of the morphometric analysis are provided.