Molecular phylogenetic and morphological evidence supports the recognition of Pseuduvaria sirindhorniana (Annonaceae), a new species from southern Thailand

Based on the molecular phylogenetic analyses of six plastid DNA regions ( mat K and rbc L exons; trn L intron; atp B- rbc L, psb A- trn H and trn L- trn F intergenic spacers) and including 57 samples of Pseuduvaria , as well as thorough morphological studies, Pseuduvaria sirindhorniana ( Annonaceae , Miliuseae ) is described and illustrated here as a new species from Narathiwat, southern Thailand. The new species belongs to a major clade that also includes P. fragrans , P. gardneri , P. glossopetala , P. kwangtungensis , P. multiovulata and P. phuyensis . Pseuduvaria sirindhorniana is morphologically most similar to P. glossopetala , but differs by having basally connate (vs. free) sepals, larger petals, elliptic-ovate (vs. obovate) outer petals, inner petals that are only connivent at the apex (vs. connivent from the base to ± the midpoint and at the apex), with openings formed from the base (vs. openings formed from ± the midpoint). Pseuduvaria kwangtungensis turns out to be a putative sister of the new species, but the two are morphologically dissimilar in several traits, such as leaf base, inner petal appearance and glands on the inner side of the inner petals.