2.1 Plant material
Primulina heterotricha is an endemic perennial shrub with thick rhizome that inhabits limestone or granite streamsides in forested valleys, widely distributed in south-central mountain systems of Hainan Island (Li & Wang, 2005; Wei, 2010; Yang, 2013). Its populations display a limited range of morphological diversity including irregular pale yellow or purple corollas. The plant has zygomorphic tubular flowers which are pollinated by several insects, especiallyGlossamegilla malaccensis (Anthophoridae) Friese and G. yunnanensis Wu (Anthophoridae)(Ling, 2017). The capsule is erect with small brown and fusiform shaped seeds, indicating a weak dispersal capability with no wind- or animal-mediated dispersal features.