A striking new species of Begonia, B. joshii, is described from Amazonas Region, Peru. The new species is unusual among the South American members of the genus both in its combination of tuberous habit with peltate leaves and in living in a seasonally dry tropical forest environment. A phylogeny of this and closely related species is presented, and its sectional affiliation and IUCN conservation status are discussed. A key to the peltate Peruvian species of Begonia is provided.

Two new infraspecific taxa of Begonia micranthera Griseb. are described. Begonia micranthera subsp. albonervia Tebbitt is described and illustrated as a new subspecies native to the Andes of southern Bolivia (Chuquisaca, Cochabamba and Santa Cruz Departments). Begonia micranthera subsp. micranthera var. flava Andrada & Bulacio is newly described from Argentina's Jujuy Province. Begonia micranthera var. rhacophylla Irmsch. is raised to subspecies and newly recorded from Bolivia. Begonia micranthera var. hieronymi (Lindau) L.B.Sm. & B.G.Schub. is recognised as B. micranthera subsp. rhacophylla var. hieronymi (Lindau) L.B.Sm. & B.G.Schub. The type collection of Begonia micranthera var. foliosa L.B.Sm. & B.G.Schub. is newly recognised as a hybrid between B. micranthera Griseb. subsp. micranthera and B. micranthera subsp. rhacophylla (Irmsch.) Tebbitt. Begonia micranthera var. fimbriata L.B.Sm. & B.G.Schub. is newly synonymised with B. cinnabarina Hook. Begonia cinnabarina is newly recognised from Argentina and is lectotypified. Begonia micranthera subsp. micranthera var. nana L.B.Sm. & B.G.Schub. is also lectotypified. A key, diagnoses and illustrations are provided for all the recognised infraspecific taxa of Begonia micranthera.

Begonia speculum is described and illustrated as a new species endemic to the San Martín Region of Peru, and compared with Begonia cremnophila Tebbitt and Begonia lutea L.B.Sm. & B.G.Schub. Begonia erythrothrix is described and illustrated as a new species endemic to the Cuzco Region of Peru, and compared with an updated description of Begonia thyrsoidea Irmsch., which is lectotypified. Using International Union for Conservation of Nature criteria, Begonia speculum is considered Vulnerable; B. erythrothrix and B. thyrsoidea are assessed as Data Deficient.

Two new species of Begonia (Begoniaceae) from Andean South America are described and illustrated. Begonia heliantha Tebbitt is classified in B. sect. Eupetalum and is known from the Puno Region of Peru and has also been tentatively identified from photographs taken in La Paz Department of Bolivia. Begonia urubambensis Tebbitt is affiliated with a group of species currently classified in B. sect. Knesebeckia. This group of species is informally named here the B. acerifolia group. Begonia sect. Knesebeckia is polyphyletic since the B. acerifolia group does not include the type species of the section. Ongoing research aims to recircumscribe this section. Begonia urubambensis is not assigned to a section given the changes needed to the sectional classification system. Begonia urubambensis is a narrow endemic of La Convención Province (Cusco Region) of Peru. Begonia heliantha is assigned the IUCN category of Data Deficient (DD), while B. urubambensis is assigned the IUCN category of Vulnerable (VU-D2).