Impatiens zhuxiensis (Balsaminaceae), a new species of Hubei, China

A new species of Impatiens L. from Hubei, China, Impatiens zhuxiensis Q.L. Gan & X.W. Li, is described and illustrated. Impatiens zhuxiensis resembles I. nasuta Hook. f. and I. compta Hook. f. and these are the only species in I. sect. Impatiens with a long abaxial rostrum on the midvein of the dorsal petal. However, the flowers of I. zhuxiensis are yellow while those of I. nasuta and I. compta are deep purple-red and pale purple-blue, respectively; I. zhuxiensis has the midvein of the dorsal petal abaxially elongated into a pointed rostrum near the apex, whilst the rostrum of I. nasuta is elephant-trunk-shaped near the middle, and that of I. compta is recurved near the apex. A molecular phylogenetic analysis of Impatiens based on ITS, atpB-rbcL and trnL-F supported these three species as closely allied and that they belong to I. sect. Impatiens.