2n = 2x = 24 voucher: Salas et al. 7332 (CIP, MOL, PTIS) (Hijmans, et al. 2007)
Solanum sogarandinum is known from northern Peru (Dept. Cajamarca), south to central Peru (Dept. Lima), growing in grasslands, jalca formations, brush fields, or altiplano, often with Stipa ichu (Ruiz & Pav.) Kunth, among rocks, in clay or sandy soil; 2800-4100 m in elevation.
Solanum sogarandinum is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, the relationships are unclear. Based on plastid DNA restriction site data (Spooner and Castillo, 1997), S. sogarandinum is a member of a distinctive clade of southern Ecuadorian and Peruvian species that frequently possess moniliform tubers and shiny coriaceous leaves. However, S. sogarandinum does not possess these morphological characters, and it is morphologically similar to S. boliviense and S. raphanifolium that are members of a clade related to the cultivated potato. On a higher taxonomic level, S. sogarandinum is a member of the informally-named Potato Clade, a group of perhaps 200-300 species that also includes the tomato and its wild relatives (Bohs, 2005).
Solanum sogarandinum is difficult to distinguish from S. boliviense Dunal and S. raphanifolium Cárdenas and Hawkes, two species classified by Hawkes (1990) and Ochoa (1999) in series Megistacroloba Cárdenas and Hawkes. Solanum sogarandinum is distinguished from both of the above by plastid DNA (see phylogeny, above) and single-copy nuclear DNA (Giannattasio and Spooner, 1994b). The species has been shown to be distinguished with difficulty from S. boliviense with morphological phenetics (Giannattasio and Spooner, 1994a), but only by characters that overlap in range.
Despite the above experimental studies, it is very difficult to differentiate S. sogarandinum from S. boliviense morphologically, especially on herbarium sheets that often lack clear indications of habit and corolla shape. Solanum sogarandinum is distinguished from S. raphanifolium by its low rosette habit and from S. boliviense by its rotate corolla. In addition, it has a distinctive non-overlapping range from both of the above species, with a distribution from northern to central Peru (Lima Department), whereas the other two are distributed from Huancavelica Department southward.
Hawkes, J.G. 1990. The potato: evolution, biodiversity and genetic resources.
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Giannattasio, R. & D.M. Spooner 1994. A reexamination of species boundaries and hypotheses hybridization concerning Solanum megistacrolobum and S. toralapanum (Solanum sect. Petota, series Megistacroloba): molecular data.
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Spooner, D.M. & R. Castillo-T 1997. Reexamination of series relationships of South American wild potatoes (Solanaceae: Solanum sect. Petota): evidence from chloroplast DNA restriction site variation.
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Hijmans, R., T. Gavrilenko, S. Stephenson, J. Bamberg, A. Salas & D.M. Spooner 2007. Geographic and environmental range expansion through polyploidy in wild potatoes (Solanum section Petota).
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