A new species of Polylepis (Rosaceae) from the Oxapampa-Asháninka-Yánesha Biosphere Reserve, Perú

A new species of Polylepis from the humid Puna in the Oxapampa-Asháninka-Yánesha Biosphere Reserve (BIOAY), Pasco Region, Perú, is described and illustrated. This species was found between 3700–3850 m elevation, on Rocky Mountains, in small patches or relict forests of the buffer zone of Yanachaga Chemillén National Park. Polylepis yanesha is similar to P. rocio-rojasii but differs because the leaves have much smaller oblong-elliptic leaflets, the abaxial surface is densely lanuginose with scattered filiform glandular trichomes of golden yellow resin, shorter and thinner petioles, the inflorescence is short, axillary, pendulous, 4.0–8.0 cm long with 5–8 flowers, a greater number of stamens, 17–23; the fruits are much smaller, rounded-ovoid to cylindrical achenes, with short, blunt-tipped spines. We also present details on its geographic distribution, ecological notes, a key to differentiating species of the genus Polylepis sect. Sericeae, a comparative table of characteristics between similar species, and an assessment of the conservation status of the new species.