Abstract
In 2013, an unidentified species of Dendrochilum appeared in cultivation under the commercial trade name 'Big Pink'. Using sequences of the nuclear ribosomal ITS1-5.8S-ITS2 region and of the plastid matK and ycf1 genes, we examined the phylogenetic relationships between 'Big Pink' and six other species of the phenetically defined Dendrochilum subgen. Platyclinis sect. Eurybrachium. Separate and combined analyses (using Bayesian, Maximum Likelihood and Parsimony inference) showed consistent placement of the unidentified species within a statistically well supported clade. Furthermore, the multi-copy nrITS marker showed clear distinct peaks. Thus, we found no evidence that 'Big Pink' could be a hybrid. Against this background, and further supported by species-specific mutations in (at least) nrITS and ycf1, we formally describe 'Big Pink' as a new species under the name Dendrochilum hampelii. Morphologically, it is most similar to Dendrochilum propinquum, but it differs in a number of characters. Of the two cultivated individuals available for our study, one was of unrecorded provenance. The other allegedly originated from the Philippines. Observations of the species occurring in the wild in the Philippines in the northern provinces of Bukidnon and Misamis Oriental on the island of Mindanao confirmed this.