Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum buesii

Citation author: 
Rev. Argent. Agron. 10: 396. 1943.
Peru. Cuzco: Urubamba, ruins of Puyupata, 3600 m, 5 Aug 1942, C. Vargas 2877 (holotype: CUZ; isotypes: CUZ, CUZ [Correll neg. 943, F-1602981, LL, MO-5609727, NY, UC1152194], LL [LL00000651] [Correll neg. 31, F-1604425, LL, MO-5609727, NY, UC1152194]).
Last edited by: 
Sandra Knapp (August 2014)
Written by: 
David M. Spooner & Diego Fajardo
Herbs 0.6-0.9 m tall, semierect to erect. Stems 8-10 mm in diameter at base of plant, green to green mottled with purple at the base, with straight wings 1 mm or more, sparsely pubescent; tubers typically borne singly at the end of each stolon.
Sympodial structure: 
Sympodial units tri- to plurifoliate, not geminate.
Leaves odd-pinnate, the blades 8-27 x 5-16.5 cm, chartaceous, densely pubescent adaxially and abaxially; lateral leaflet pairs 3-4, subequal or decreasing in size gradually toward the leaf base, with the terminal leaflet equal to or slightly larger than the laterals; most distal lateral leaflets 2.5-8 x 1-2.5 cm, elliptic-lanceolate to lanceolate, the apex long acuminate, the base with petiolules 2-9 mm, symmetrical; terminal leaflet 3.7-8 x 1.2-3.4 cm, elliptic-lanceolate to lanceolate, the apex acuminate, the base round or obtuse, with secondary leaflets on the petiolule typically absent; interjected leaflets 2-10, subsessile, ovate to orbicular; petioles 1.5-7 cm, sparsely pubescent. Pseudostipules minute to 5 mm long, pubescent with hairs like those of the stem.
Inflorescences 6.5-12.7 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 8-14 flowers, with all flowers apparently perfect, the axes densely pubescent; peduncle 2.4-3.6 cm long; pedicels 10-28 mm long in flower and fruit, spaced 1-10 mm apart, articulated in the middle to distal ¼.
Flowers homostylous, 5-merous. Calyx 7-9 mm long, the tube 1-2 mm, the lobes 4-6 mm, long acuminate, the acumens 0.2-0.5 mm long, densely pubescent. Corolla 3-4 cm in diameter, rotate-stellate, purple-violet, often with a green star at the base of the corolla adaxially and a white stripe on the middle of each lobe abaxially, the tube 1-2 mm long, the acumens 3-5 mm long, the corolla edges flat, not folded dorsally, glabrous adaxially, minutely puberulent abaxially, especially along the midribs, ciliate at the margins, especially at the tips of the corollas. Stamens with the filaments 1-2 mm long; anthers 5-8 mm long, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 7-9 mm x ca. 1 mm, exceeding stamens by 1.2-3.6 mm; stigma capitate.
Fruit a long conical berry, 1.7-2.5 cm long, ca. 1.4 cm wide, light green when ripe, glabrous.
Seeds from living specimens ovoid and ca. 2 mm long, whitish to greenish in fresh condition and drying brownish, with a thick covering of “hair-like” lateral walls of the testal cells that make the seeds mucilaginous when wet, green-white throughout; testal cells honeycomb-shaped when lateral walls removed by enzyme digestion.
Chromosome number: 

2n = 2x = 24 voucher: Ochoa 14361 (CUZ) (Hijmans, et al. 2007)


Solanum buesii is endemic to southern Peru (Dept. Cuzco), in moist habitats, on forest margins; 2400-3650 m in elevation.

Flowering and fruiting from February to September.

Solanum buesii is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, Solanum buesii is a member of a distinctive group of species formerly classified in series Conicibaccata (see below). 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 (1990) treated Solanum buesii as one of 40 species in Solanum sect. Petota series Conicibaccata Bitter, a group containing diploids (2n = 24), tetraploids (2n = 48), and hexaploids (2n = 72). The polyploids are mainly distributed from southern Mexico south to central Peru (one species in northern Bolivia), and the diploids from northern Peru to central Bolivia.

The species boundaries and relationships of members of series Conicibaccata have been studied using plastid DNA restriction sites (Castillo and Spooner, 1997), morphology (Castillo and Spooner, 1997; Fajardo et al., 2008), AFLPs (Jiménez et al., 2008), nuclear DNA (“waxy”) sequence data (Spooner et al., 2008), other nuclear DNA sequence data (Fajardo & Spooner 2011), and monographic studies (Hawkes, 1990; Hawkes and Hjerting, 1989; Ochoa, 1990, 1999). The plastid DNA restriction site and morphological data divide the diploids and polyploids into two clades or phenetic groups, respectively, but the morphological separation generally depends on the use of character states that sometimes overlap in range. The DNA sequence data show the polyploids to be of allopolyploid origin from the diploid members of the series and members of species outside of the series.

A monographic study in progress by Fajardo and Spooner, using the above data, and herbarium specimens, will recognize only 17 species. All are very similar, united as a group by conical fruits, leaves with generally parallel-sided morphology, and narrowly ovate to elliptical leaflets. However, some unrelated species also have conical fruits, such as the Mexican diploid species S. hintonii Correll, S. lesteri Hawkes and Hjert. and S. trifidum Correll; the Mexican hexaploid species S. iopetalum (Bitter) Hawkes; and the Bolivian species S. circaeifolium Bitter. An additional problem is that some species possess ovoid fruits that are not absolutely distinct from the conical fruits of the above species or the globose fruits more common in the majority of the members of sect. Petota.

Solanum buesii is characterized by its densely pubescent leaves and calyx, elliptic-lanceolate terminal and lateral leaflets, long acuminate calyx and corolla acumens, and rotate-stellate purple-violet corollas.


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.

Castillo-T., R., & D.M. Spooner 1997. Phylogenetic relationships of wild potatoes, Solanum series Conicibaccata (sect. Petota). Syst. Bot. 22: 45-83.

Fajardo, D., R. Castillo, A. Salas, & D.M. Spooner 2008. A morphometric study of species boundaries of the wild potato Solanum series Conicibaccata: a replicated field trial in Andean Peru. Syst. Bot. 33: 183-192.

Fajardo, D. & D.M. Spooner. 2011. Phylogenetic relationships of Solanum series Conicibaccata and related species in Solanum section Petota inferred from five conserved ortholog sequences. Syst. Bot. 36:163-170.

Hawkes, J.G. & J.P. Hjerting 1989. The potatoes of Bolivia: their breeding value and evolutionary relationships. Oxford University Press, Oxford.

Hawkes, J.G. 1990. The potato: evolution, biodiversity and genetic resources. Oxford: Belhaven Press.

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.

Jiménez, J.P., A. Brenes, A. Salas, D. Fajardo & D.M. Spooner 2008. The use and limits of AFLP data in the taxonomy of polyploid wild potato species in Solanum series Conicibaccata. Conserv. Genet. 9: 381-387.

Ochoa, C.M. 1999. Las papas de sudamerica: Peru (Parte I). Lima, Peru: International Potato Center.

Spooner, D.M., F. Rodríguez, Z. Polgár, H.E. Ballard Jr. & S.H. Jansky 2008. Genomic origins of potato polyploids: GBSSI gene sequencing data. The Plant Genome, a suppl. to Crop Sci. 48 (S1): S27–S36.

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