Molecular and Morphological Analyses Support the Transfer of Gleadovia kwangtungensis to Christisonia (Orobanchaceae)

Abstract—

Christisonia kwangtungensis is a new combination proposed in this study on the basis of both molecular and morphological evidence. The basionym, Gleadovia kwangtungensis, was subsumed into Christisonia hookeri by Zhang in 1986. Because the type material of C. hookeri lacks important diagnostic characters and no fresh materials from Sikkim were available, Chinese plants with white flowers were conservatively treated as C. sinensis. Phylogenetic analyses showed that samples of G. kwangtungensis from the type locality on Danxia Mountain were monophyletic and sister to a clade including the reciprocally monophyletic C. sinensis and C. siamensis. Moreover, morphological comparisons showed that C. kwangtungensis differs from C. sinensis by having a conspicuously inflated (vs. scarcely inflated) corolla and clustered hairs in the throat of the corolla (vs. hairs scattered throughout the interior of the corolla). Further, C. kwangtungensis differs from both C. sinensis and C. siamensis by the length and color of the corolla.