Impatiens maculifera (Balsaminaceae), a new species from Yunnan, China

27 June 2019

xia, changying; Gadagkar, Sudhindra; zhao, xinlei; Do, Truong; Zhu, Xiang-Yun; qin, ying; Deng, Hong-Ping; YU, Shengxiang

Background: Impatiens, belonging to the family Balsaminaceae, is a large genus distributed mainly throughout much of tropical Africa, India, Southwest Asia and southern China. While it is a notoriously difficult taxon to study for reasons that include small, remote, and endemic areas of occurrence, and difficulty in obtaining well-dried herbarium specimens and separating and reconstructing floral parts from available dried specimens, new species of Impatiens are frequently being discovered. Due to these and other reasons, Impatiens has been a notoriously difficult taxon for phylogenetic resolution at the infrageneric level. Yu et al. (2015) proposed a new classification outline, based on both morphological and molecular evidence, in which Impatiens is divided into two subgenera, subgenus Clavicarpa and subgen. Impatiens; the latter is further subdivided into seven sections. The new classification has made it easier to organize the taxonomy of existing and newly discovered Impatiens species.
Results: Impatiens maculifera, a new species of Balsaminaceae from Malipo County, Yunnan, China is similar to I. parvisepala S.X. Yu & Y.T. Hou in having racemose inflorescences, 4 lateral sepals, clavate capsules and ellipsoid seeds, but differs in having leaves narrow oval or with elliptic-lanceolate blades (vs. obovate or obovate-lanceolate), petiole obvious (vs. subsessile), inflorescence with 8-12 flowers racemose (vs. 6-8 flowers), flowers greenish yellow (vs. yellow), lateral united petals and lower sepal with dense red spots (vs. red spots absent), and dorsal petal with apparent stalk at base (vs. unapparent stalk). Morphological characters and molecular phylogenetic analyses of DNA sequences from both nuclear ribosomal and plastid genes show that this taxon differs distinctively from I. parvisepala, thus indicating that I. maculifera is a new species.
Conclusion: Impatiens maculifera is distinguished from other Impatiens species based on morphological, micromorphological and palynological evidence, and molecular data. Therefore, we believe that it is new to science.