New taxa and a new combination in Tidestromia (Amaranthaceae) from North America

A new species and a new subspecies of Tidestromia are described and illustrated. Tidestromia valdesiana, restricted to Coahuila, Mexico, is characterized by the absence of an involucre and tepals lanceolate, aristate at the apex with a prominent midnerve and subulate trichomes. Tidestromia lanuginosa subsp. eliassoniana is characterized by having trichomes with the terminal cell projections either irregular (as those of the subsp. lanaginosa) or spreading, and microspinulose pollen, which is unique within the genus. A distribution map for the two recognized subspecies of T lanuginosa is provided. The new combination T. suffruticosa var. oblongifolia is proposed, and T oblongifolia subsp. cryptantha is reduced to synonymy under the former; both names are lectotypified.