Taxonomic review of the species of Parkinsonia (Leguminosae, Caesalpinioideae) from the Americas

Abstract The genus Parkinsonia has a pantropical distribution with 12 species globally, occurring mainly in arid and semi-arid climate environments. Many taxonomic studies have considered as distinct of Cercidium, but phylogenetic analyses do not support this distinction because, when together, they form well-supported monophyletic group. aim study was to review the taxonomy from Americas. We examined 400 specimens deposited herbaria, original diagnoses, types. present here morphological descriptions, identification key, notes nomenclatural notes, ecology conservation status, reproductive phenological states, maps drawings for each treatment. Our points out eight Americas (P. aculeata, P. andicola, florida, glauca, microphylla, peruviana, praecox, texana), three new synonyms (Cercidium macrum, inermis, texana var. macra) six lectotypifications plurifoliolatum, C. spinosum, texana). main diagnostic characteristics are green or gray stem, branches generally thorns, reduced leaves (pinnate appearance) (bipinnate), hyphodromous venation, racemose inflorescences, yellow petals moniliform flat pod fruit.