Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum colombianum

Citation author: 
Dunal
Citation: 
in DC., Prodr. 13(1): 33. 1852.
Type: 
Colombia. Sin. loc., J.W.K. Moritz 829 (holotype: G-DC [Correll neg. 28, BM000882101, F-1604421, LL, NY, UC1152249]; isotypes: BM [Correll neg. 27, F-1604422, LL, MO-5588159, MO-559440, NY, UC1152249], BM000565900, BM000565901, [Correll neg. 69, BM000882098, F-1604866, LL, NY, UC1152249], G-DEL [F neg. 6756, F-645051, MO-1690933, NY], HBG-2 sheets [photo of undetermined source, MO-5588158], LE).
Last edited by: 
Sandra Knapp (August 2014)
Written by: 
David M. Spooner & Diego Fajardo
Habit: 
Herbs 0.3-2.2 m tall, semierect to erect. Stems 2-13 mm in diameter at base of plant, green to green mottled with purple, unwinged or with wings to 0.8 mm wide, subglabrous to finely puberulent with whitish simple hairs; tubers typically moniliform (multiple tubers arranged along the stolon like beads on a necklace).
Sympodial structure: 
Sympodial units tri- to plurifoliate, not geminate.
Leaves: 
Leaves odd-pinnate, the blades 6.5-52 x 3.5-22 cm, medium to dark green, membranous to chartaceous, finely to coarsely pubescent adaxially and abaxially with hairs like those of the stems; lateral leaflet pairs 2-5, subequal or the leaflets decreasing in size gradually toward the leaf base, with the terminal leaflet subequal to the laterals; most distal lateral leaflets 1.9-10 x 0.5-3.2 cm, ovate to elliptic, the apex acuminate, the base subsessile or with petiolules to 6 mm, symmetrical to more commonly asymmetrical with more tissue on the basiscopic side; terminal leaflet 2-12.2 x 0.8-5.8 cm, ovate to elliptic, the apex acuminate, the base attenuate, rarely with secondary leaflets on the petiolule; interjected leaflets 0-11, sessile, ovate to orbicular; petioles 1-9.5 cm, finely to coarsely pubescent with hairs like those of the stems. Pseudostipules minute to 10 mm long, pubescent with hairs like those of the stem.
Inflorescences: 
Inflorescences 6-17.5 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 4-38 flowers, with all flowers apparently perfect, the axes finely to coarsely pubescent with hairs like those of the stem; peduncle 4-12.5 cm long; pedicels 13-36 mm long in flower and fruit, spaced 1-10 mm apart, articulated between the proximal fourth to the distal fourth.
Flowers: 
Flowers homostylous, 5-merous. Calyx 4-11 mm long, the tube 1-2 mm, the lobes 4-8 mm, long attenuate, the acumens 0.8-3.1 mm long, glabrous to subglabrous. Corolla 2-4.2 cm in diameter, pentagonal to rotate, white throughout to white tinged with purple or violet to purple or violet throughout, the rays sometimes darker purple or white, the tube 1-2 mm long, the acumens 0.8-3.1 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 3.3-6.1 mm long, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 6-10 mm x ca. 1 mm, exceeding stamens by 0.6-3.3 mm, straight, glabrous; stigma clavate to capitate.
Fruits: 
Fruit a conical berry, 1-2.5 cm long, 0.7-2.4 mm wide, medium to deep green when ripe, glabrous.
Seeds: 
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 = 6x = 72 voucher: Castillo et al. 1243 (PTIS) (Hijmans, et al. 2007)
2n = 4x = 48 voucher: Castillo et al. 1212 (PTIS) (Hijmans, et al. 2007)

Distribution: 

Solanum colombianum occurs in northern South America from western Venezuela (Distrito Federal) to northern Peru (Dept. Cajamarca), in moist habitats, often in rich organic soils, in sunny openings in woods or at forest edges, or in páramo among shrubs, often in disturbed habitats such as streamsides or roadsides or landslides, or in recently burned woods or forest clearings where populations can be extensive; 1800-3950 m in elevation. Plants previously identified as S. colombianum from Panama are now recognized as S. woodsonii.

Phenology: 
Flowering and fruiting throughout the year.
Phylogeny: 

Solanum colombianum is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, Solanum colombianum 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).

Commentary: 

Hawkes (1990) treated Solanum colombianum 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, is recognizing 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 colombianum is by far the most widely distributed and polymorphic polyploid member of the series, composed of both tetraploid cytotypes (such as the previous name S. colombianum and others), and the hexaploid cytotypes S. moscapanum, S. sucubunense and S. tundalomense. Relative to the other South American polyploids, S. colombianum may be a plesiospecies (sensu Rieseberg and Brouillet, 1994; Olmstead, 1995), with the other sympatric polyploids (S. flahaultii Bitter, S. garcia-barrigae Ochoa, and S. lobbianum Bitter) as phenetically distinctive local derivatives. Its polymorphism and possible plesiomorphic species status make it hard to define, and is best differentiated from other polyploids by lack of characters that define them. These include, for example, the lack of a seed spot found in S. longiconicum, lack of an enlarged or differently shaped terminal leaflet in comparison to lateral leaflets as in S. garcia-barrigae or S. pillahuatense, lack of densely pubescent leaves as in S. lobbianum.

Dunal (1852) described S. otites based on Linden 426 in the Boissier Herbarium at G. There are two specimens of Linden 426 at G but only one bears Dunal’s handwriting that we consider as holotype. Both of these specimens have three pairs of lateral leaflets (3-jugate) We consider duplicates of this collection at BR, FI, G, OXF and P as isotypes. Bitter (1912) redescribed S. otites as a species both 2- and 3-jugate, but described two forms (forma dizygum and forma trizygum) differing in this character. A sheet at W bears two specimens differing in 2- vs. 3-jugate leaves with his handwriting describing this variation that we consider as type material.

References: 

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.

Olmstead, R.G. 1995. Species concepts and plesiomorphic species. Syst. Bot. 20: 623-630.

Rieseberg, L.H. & L. Brouillet 1994. Are many plant species paraphyletic? Taxon 43: 21-32.

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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