Taxonomic placement of Paphiopedilum canhii (Cypripedioideae; Orchidaceae) based on cytological, molecular and micromorphological evidence

•Molecular and morphological data confirmed that Paphiopedilum canhii should be placed in a separate taxon.•Number of chromosomes in P. canhii is 2n = 26 and this is the basic number of chromosomes for the genus.•Nuclear an plastid data stay in conflict according to position of P. canhii.

Paphiopedilum canhii was discovered in Northern Vietnam. Since its description in 2010, it has caused a stir among taxonomists due to its interesting mixture of morphological features, i.e. marbled, relatively thick leaves, flowers similar to species classified in the section Barbata, and unique, large staminodial shield. On the basis of these features, it is difficult to classify the species to existing infrageneric units. Using cytological data, phylogenetic analyses based on plastid and nuclear genes and the study of the adaxial epidermis of the leaves and gynostemium structure obtained from Scanning Electron Microscopy (SEM) and Light Microscopy (LM), the taxonomic position of P. canhii was determined. These results suggest that P. canhii forms an independent phylogenetic line within the genus Paphiopedilum deserving subgeneric status, already proposed by Braem and Gruss (2011) as Megastaminodium.

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