The family placement of Cyrtandromoea

Cyrtandromoea is a genus consisting of about 12 species of perennial caulescent herbs with a distribution in China, India, Myanmar, Thailand, and western Malesia. The genus has previously been associated with either Gesneriaceae or the tribe Mimuleae in Phrymaceae (in former Scrophulariaceae) with morphology in favor of the latter and molecular plastid ndhF data the former. We addressed the placement of this genus by assembling a four gene dataset (matK, ndhF, rps16, and trnL-F) comprising 270 ingroup samples representing 270 species and 51 families of the core asterids, including all families of Lamiales currently recognized. These included 111 species representing 66 genera of Gesneriaceae. We used maximum parsimony, maximum likelihood, and Bayesian inference analyses to reconstruct phylogenies that showed Cyrtandromoea to be placed in Phrymaceae. A fine-scale analysis focusing on Phrymaceae using ITS and trnL-F and 79 samples revealed that Cyrtandromoea is most closely related to a clade of genera in Phrymaceae that included Mimulus s. s. A combination of morphological synapomorphies such as cymose inflorescences, 5-angled toothed calyx, flowers with bilocular ovary with axile placentation with numerous small seeds with endosperm, and loculicidal dehiscing capsule support this placement. Our results strongly support the placement of Cyrtandromoea in Phrymaceae.