Camelliayangii (Theaceae), a new species of tea plants (Camellia section Thea).

Camelliasect.Thea contains plants of beverage sources with huge profits. Their natural germplasm resources have yet to be fully explored. Here, morphological, phenological and phylogenetic analyses were undertaken to reveal a new species of tea plants, C.yangii D.Wei Zhao. It is described with an illustration and photos of fresh characters provided. The new species is similar to C.fangchengensis and C.ptilophylla by the densely pubescent new branchlets, abaxial surface of leaves and pedicel, but differs from them in bearing a larger flower, fewer (3 vs. 5) but larger sepals, and the indumentum of the sepals. Molecular phylogenetic analysis using RPB2 introns 11-15 and 23 and waxy suggests that it is a member of C.sect.Thea and its phylogenetically closely related species are C.longissima and C.taliensis. Camelliayangii has a later flowering phase compared with other taxa of C.sect.Thea that occurred or were planted nearby, so it cannot naturally hybridize with other tea plants. The new species bears a red or purplish red and densely pubescent terminal bud, which suggests it is a rare germplasm resource of tea plants. Camelliayangii is only known from a single extremely vulnerable population and strict conservation and asexual propagations are urgently needed to avoid extinction.