Solanum falciforme is endemic to Brazil. Found in cerrado and along roadsides, 380–1300 m in elevation, common in States of Goiás and Distrito Federal, but also occurring in Bahia and Minas Gerais.
Solanum falciforme is a member of the Crinitum/Androceras clade (sensu Stern et al. 2011), section Crinitum sensu stricto.
Within Solanum section Crinitum, Solanum falciforme most closely resembles Solanum lycocarpum A. St.-Hil., Solanum gomphodes Dunal and Solanum crinitum Lam. All four species have pubescence of sessile to short-stalked porrect-stellate hairs and distributions centered in eastern Brazil. Solanum gomphodes can be easily distinguished from Solanum falciforme by its sessile leaves (vs. petioles usually 3–5 cm long in Solanum falciforme) and exclusively short-stalked stellate hairs. Solanum lycocarpum and Solanum crinitum are sympatric with Solanum falciforme, but the former two species have much broader distributions throughout South America. Solanum falciforme is easily distinguished from S. lycocarpum and S. crinitum by the presence of macroscopic falcate (sickle-shaped) long-stalked bristly hairs on the young stems as well as the inflorescence and calyx. Collections of Solanum crinitum often have similar long-stalked trichomes on the young stems, inflorescence and calyx; however the stalks of these hairs are straight. Solanum lycocarpum is similar to the other three taxa in its abundant pubescence of short-stalked stellate hairs, but the distinctive long-stalked hairs found in Solanum falciforme are noticeably absent.
For references cited here please see Farruggia & Bohs. 2010.Two new South American species of Solanum section Crinitum (Solanaceae). PhytoKeys 1: 67–77.
Brazil: Lobeiro (Costich 1017); fruto do lobo (Macedo 3245, Heringer 10718).
According to the IUCN Red List Categories (IUCN 2010), Solanum falciforme is classified asVU-B1a+biii; A2c (Vulnerable). Populations of this species are located near expanding population centers leading to highly fragmented populations. The extent of occupancy is estimated to be less than 20, 000 km2. There is also a continuing decline in suitable habitat in these regions due to deforestation and the establishment of new settlements.