2n = 3x = 48 voucher: Okada 6769 (BAL) (Hijmans, et al. 2007)
2n = 4x = 48 voucher: Okada 6055 (BAL) (Hijmans, et al. 2007)
Solanum ×aemulans is found in northern Argentina (Provs. Jujuy, Salta and La Rioja), in generally dry rocky areas, in railway embankments, among spiny shrubs or cacti, at the edges of cultivated fields or roadsides, along streamsides and ditches, close to stone walls of cattle enclosures as well as on bare soil; (2690) 3000-4000 (4020) m in elevation.
Solanum ×aemulans is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, Solanum ×aemulans is a member of a very diverse clade related to the cultivated potato. On a higher taxonomic level, it 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).
Hawkes, J.G. & J.P. Hjerting 1969. The potatoes of Argentina, Brazil, Paraguay and Uruguay: a biosystematic study.
Oxford Univ. Press, Oxford, UK.
Okada, K.A. & A.M. Clausen 1982. Natural hybridization between Solanum acaule Bitt. and S. megistacrolobum Bitt. in the Province of Jujuy, Salta.
Euphytica 31: 817-835.
Hawkes, J.G. & J.P. Hjerting 1989. The potatoes of Bolivia: their breeding value and evolutionary relationships.
Oxford University Press, Oxford.
Hosaka, K. & D.M. Spooner 1992. RFLP analysis of the wild potato species, Solanum acaule Bitter (Solanum sect. Petota).
Theor Appl Genet 84: 851-858.
Nakagawa, K., H. Uehara & K. Hosaka 2000. Chloroplast DNA variation in the wild potato species, Solanum acaule and S. albicans.
Euphytica 116: 197-202.
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.
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).
Global Ecol. Biogeogr. 16: 485-495.
Solanum ×aemulans is distributed in two disjunct areas of Argentina in 1) Jujuy and Salta Provinces, 2) La Rioja Province. Triploid and tetraploid cytotypes are found in the northern range of its distribution (Jujuy and Salta), while only tetraploids occur in the Province of La Rioja. This species is frequently found growing with the following tuber-bearing species: S. acaule, S. oplocense, S. infundibuliforme, S. boliviense and S. brevicaule.
Solanum ×aemulans can be differentiated from S. acaule by the presence of the articulated pedicel, by its larger stamens, and frequently by the strong scent of the leaves. From S. megistacrolobum it can be differentiated by the number of lateral leaflets and by the rotate to rotate pentagonal corollas. From S. ×viirsooi it can be differentiated by the broadly ovate to lateral leaflets and by the rounded apex of the terminal leaflet.
A natural triploid hybrid of S. acaule × S. boliviense (referred to as S. megistacrolobum) was described by Okada and Clausen (1982) as S. ×indunii, as this nothospecies possesses characters of both parental species and co-occurs with them. These populations are common in northwest Argentina and were differentiated from S. acaule ssp. aemulans on the basis of minor morphological characters. Furthermore, these authors pointed out that the populations from Tilcara (Jujuy Province) of S. acaule ssp. aemulans and the hybrids of S. acaule x S. megistacrolobum had characters in common which could be interpreted as having a similar origin through the functioning of 2n gametes that could have resulted in a fertile hybrid tetraploid. Hosaka and Spooner (1992) were able to differentiate the two disjunct populations of aemulans on the basis of single-to low-copy nuclear DNA, but Nakagawa et al. (2002) could distinguish these on the basis of plastid DNA restriction site data.
We group the triploids (S. ×indunii) and tetraploids (S. ×aemulans ) together because of likely common origins and because they are morphologically indistinguishable, and we group the two sets of tetraploids together because they are morphologically indistinguishable. However, S. boliviense does not occur in the southern distribution range in La Rioja Province and as mentioned above they can be distinguished with plastid and nuclear DNA markers. Hawkes and Hjerting (1989) consider S. acaule not very closely related to any other wild potato species, although they point out similarities with species of the series Megistacroloba. They agree with Okada and Clausen (1982) in their interpretation of the hybrid origin of aemulans from Tilcara but consider that this interpretation is not valid for the type material from La Rioja, since S. megistacrolobum has not been found there.