Chile [Regions I (Tarapacá), II (Antofagasta), III (Atacama), IV (Coquimbo), and V (Valparaíso)] and Peru (Departments of Ancash, Arequipa, Lima, Ica, La Libertad, Lambayaque, Moquegua, and Tacna). On sandy or rocky lomas, 5–3400 m in elevation.
This species belongs to the Regmandra clade of Bohs (2005), an isolated clade within the non-spiny solanums.
Hooker, W.J. 1827. Witheringia montana. Mountain Witheringia, or St. Lorenzo Potatoe.
Curtis's Bot. Mag. 54(n.s.1): 2768.
Knapp, S. & C.E. Jarvis 1990. The typification of the names of New World Solanum species described by Linnaeus.
J. Linn. Soc., Bot. 104: 325-367.
Bohs, L. 2005. Major clades in Solanum based on ndhF sequences.
Pp. 27-49 in R. C. Keating, V. C. Hollowell, & T. B. Croat (eds.), A festschrift for William G. D’Arcy: the legacy of a taxonomist. Monographs in Systematic Botany from the Missouri Botanical Garden, Vol. 104. Missouri Botanical Garden Press, St. Louis.
Solanum montanum is a common plant of the lomas of coastal Peru. Some specimens are notable for the swelling of the subterranean caudex which forms a small ‘tuber-like’structure. Although this is not homologous to the true tubers of potato (S. tuberosum), this feature has given rise to its common name ‘papa de loma’. Field investigations of populations of S. montanum have shown that this character is not constant and may perhaps be related to environmental conditions (e.g. rainfall). In general, plants that develop a swollen caudex have a small, compact habit, and with leaves that are to some degree petiolate with a subentire margin (similar to the type illustration of S. montanum). In contrast, other specimens (similar to the type specimen of S. phyllanthum) have a more robust and spreading habit, with leaves that are strongly decurrent on a winged petiole and with a lobed margin. In this respect they are similar to S. paposanum from high altitude regions of Chile, with which they share the unusual arrangement of the inflorescence in which the peduncle arises some way along the midrib of a bract-like leaf. However, the leaves of S. paposanum are always densely velutinous whereas those of S. montanum are subglabrous. A whole range of intermediate forms can be found and S. phyllanthum Cav. is here reduced to synonymy with S. montanum.