Hoya longlingensis and H. sichuanensis (Apocynaceae), Two New Species from Southwestern China

Hoya longlingensis (E.F. Huang) and H. sichuanensis E.F. Huang are two new species of Apocynaceae from Southwestern China that are described in this study. Morphologically, the two species resemble H. tamdaoensis Rodda & T.B. Tran and H. lyi H. Lév., respectively. However, H. longlingensis differs from H. tamdaoensis by its elliptic leaves, mid-vein of leaf blades raised adaxially and depressed abaxially, lateral veins 2–4-paired, corolla yellow-green, outer angles of corona convex and spreading outside obviously. While H. sichuanensis differs from H. lyi by its obovate leaves, leaf apex rounded and base cuneate, petioles 1–3.5 cm long and ca. 3 mm in diameter, calyx lobes triangular, and corona whitish.