5.24. Begonia fissistyla Irmsch., Bot. Jahrb. Syst. 74: 591 (1949).

– Type: Bolivia, [La Paz Department, Sur Yungas Prov.], Unduavi Valley, [16°18′S, 67°50′W], 2000–2600 m, B. Julio 438 (syntype US [US00115312], isosyntype B ex US [B100467925]); La Paz Department, Prov. Nor-Yungas, Milluguaya, [16°22′S, 67°36′W], 1300 m, xii 1917, O. Buchtien 635 (syntypes B, HBG, US [US00222407]; isosyntype NY [NY01085495]) .

R.C. Foster, Contr. Gray Herb. 184: 137 (1958); D.C. Wasshausen et al. in P.M. JØrgensen et al. (eds), Cat. Bolivia, Monogr. Syst. Bot. Missouri Bot. Gard. 129: 384 (2013).

Begonia suprafastigiata auct. non. Irmsch. in D.C. Wasshausen et al . in P.M. JØrgensen et al. (eds), Cat. Bolivia, Monogr. Syst. Bot. Missouri Bot. Gard. 129: 386 (2013).

Distribution. Endemic to Bolivia.

Nomenclatural notes. The protologue of Begonia fissistyla cited material of the collection B. Julio 438 in the US herbarium and O. Buchtien 636 in the B, HBG and US herbaria (Irmscher, 1949). We have not been able to examine the duplicates of O. Buchtien 635 in B or HBG, and all the other cited sheets we have seen are poor. We therefore refrain from designating a lectotype.

Synonymy notes. Begonia suprafastigiata was included in the latest checklist of Bolivian Begonia based on the specimen S.G. Beck 17813 held at the LPB and US herbaria (Wasshausen et al., 2013). This specimen has the multifid styles characteristic of Begonia sect. Hydristyles and the deciduous stipules and fruit wing shape characteristic of B. fissistyla .

Identification notes. Begonia fissistyla is superficially most similar to Begonia alto-peruviana . Both species are succulent, erect herbs with early-deciduous stipules and transversely ovate leaves with entire to serrulate margins. The two species are in different sections, and Begonia fissistyla can be distinguished by its pistillate flowers with multifid styles (vs bifid) and fruits with a largest wing widest in the middle (vs widest where they are attached to the ovary). We have not been able to find any characters that distinguish specimens of these two species that lack both fruits and pistillate flowers.