Pyramidanthe and Mitrella (Annonaceae, Uvarieae) unified: molecular phylogenetic and morphological congruence, with new combinations in Pyramidanthe

Abstract: The delimitation of the genera Pyramidanthe and Mitrella in the tribe Uvarieae of the family Annonaceae is assessed by molecular phylogenetic analyses and morphological re-evaluation. Using up to six plastid DNA regions (matK, ndhF, rbcL exons; trnL intron; psbA-trnH, trnL-trnF intergenic spacers) and including, among others, two accessions of Pyramidanthe and five accessions of Mitrella, the resulting phylogeny shows that Pyramidanthe and Mitrella are recovered in a clade sister to the Fissistigma clade. The Pyramidanthe-Mitrella clade is composed of a trichotomy: a clade consisting of Pyramidanthe accessions and two clades containing Mitrella accessions. In combination with negligible morphological distinctions between the two genera, they are consequently merged, with 11 new combinations under the chosen name Pyramidanthe: P. beccarii, P. clementis, P. cylindrica, P. dielsii, P. elegans, P. kentii, P. ledermannii, P. mabiformis, P. schlechteri, P. sylvatica and P. tiwiensis. The names M. dielsii (the basionym of P. dielsii) and P. rufa (a heterotypic synonym of P. prismatica) are lectotypified. Pyramidanthe s. lat. possesses the following diagnostic traits: usually indistinct secondary leaf veins with a brochidodromous to brochidodromous-eucamptodromous venation, a reticulate tertiary leaf venation, axillary inflorescences, presence of a basal excavation on an inner side of each outer petal, and inner petals that are much smaller than the outer petals and cohering marginally at anthesis. Citation: Bangkomnate R., Damthongdee A., Baka A., Aongyong K. & Chaowasku T. 2021: Pyramidanthe and Mitrella (Annonaceae, Uvarieae) unified: molecular phylogenetic and morphological congruence, with new combinations in Pyramidanthe. – Willdenowia 51: 383–394. Version of record first published online on xx December 2021 ahead of inclusion in December 2021 issue.