Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum oxycarpum

Citation author: 
Hort. Hal. [Schltdl.] 1, 5, tab. 3. 1841.
Mexico. Veracruz: in rocky places at Malpays de La Joya, Jun 1829, C.J.W. Schiede s.n. (lectotype designated by Hawkes (1957: 851): HAL, upper right-hand specimen! [photos: MPU!, K!, PTIS!]; isolectotype: L! [photos: PTIS!, WAG!]).
Last edited by: 
Sandra Knapp (August 2014)
Written by: 
David M. Spooner
Herbaceous tuber-bearing perennials 0.5-2 m tall. Stems 2-13 mm in diameter at base of plant.
Sympodial structure: 
Sympodial units typically 3-6-foliate.
Pseudostipules to 2-10 mm long, lunate. Leaves odd-pinnate, 14-35 cm long, 10-19 cm wide, finely pubescent adaxially and abaxially; petioles 1-5 cm long; lateral leaflet pairs (3-) 5-7 (-8), subequal or the size of the lateral leaflets diminishing gradually towards the base of the leaf; most distal lateral leaflets 2.5-7.5 cm long, 1.0-2.0 cm wide, narrowly ovate to elliptical, apex acuminate, base oblique, rounded to cuneate, sessile to subsessile with petiolules up to 2 mm long; terminal leaflet 4.2-7.5 cm long, 1.0-2.2 cm wide, ovate to elliptical, apex acute to acuminate, base attenuate; interjected leaflets 4-31.
Inflorescence a dichasially branched, ebracteate, monochasial or dichasial cyme, 2-3 forked, generally in the distal half of the plant, with 8-38 flowers, all flowers perfect, peduncle 2-10.5 cm long; pedicels 15-30 mm long, articulate between the proximal ¼ and the distal ¼.
Flowers with the calyx 4.5-10 mm long, lobes acute to long-attenuate, acumens 1-4 mm long. Corollas 2-3 cm in diameter, rotate, acumens 0-5 mm, edges of corolla flat, not folded dorsally, blue to purple adaxially and abaxially. Anthers 4-5.5 mm long, connate, yellow, apically poricidally dehiscent and often maturing to a short introrse apical slit, filaments 1-4 mm long. Ovary with style 5-8 mm long, exceeding stamens by 2-3 mm, straight, with stigma globose.
Fruits 2-5 cm long, conical, obtuse to acute at tip, medium green to deep green throughout.
Seeds from living specimens green-white throughout, ovoid, ca. 2 mm long, with a thick covering of “hair-like” lateral walls of the testal cells that make the seeds mucilaginous when wet. Removal of these hair-like lateral walls by enzyme digestion reveals a honeycomb pattern at their base.
Chromosome number: 

2n = ploidy missing =48 voucher missing = (Spooner & Hijmans 2001)


Mexico (Hidalgo, Oaxaca, Puebla, Veracruz), (1520) 1870-2870 m; in wet habitats, often in openings of cloud forests, often in pine and oak, in organic soils, in full sun to partial shade, growing among shrubs and in pine-oak-alder forests, frequently in pockets of volcanic rocks, often growing among ferns and mosses.

Flowering and fruiting July through November.

Solanum oxycarpum belongs to the potato clade of Solanum (Bohs,2005). Spooner and Sytsma (1992) placed S. oxycarpum on the most terminal clade of section Petota based on chloroplast DNA restriction site data. Spooner et al. (2004) erected the Conicibaccata group to contain the Mexican and Central American species S. agrimonifolium, S. longiconicum, S. oxycarpum, and S. woodsonii. All four of these species form a “polyploid ser. Conicibaccata clade” distinguished from the diploid species of the series by chloroplast DNA and morphological data (Castillo and Spooner 1997). These four species are morphologically distinguished (sometimes with difficulty) as a group by conical fruits, leaves with a somewhat parallel-sided morphology (mentioned in the descriptions as lateral leaflet pairs subequal or diminishing gradually towards the base) and narrowly ovate to elliptical leaflets (Spooner et al. 2001). The species evaluated in North and Central America are all 4x(2EBN) (S. longiconicum is not yet evaluated for EBN, and S. woodsonii is not yet evaluated for ploidy and EBN). Some related species traditionally placed in ser. Conicibaccata in South America (see Fajardo & Spooner 2011) are also 4x(2EBN), and others are 2x(2EBN) and 6x(4EBN). All species in North and Central America, like related species in South America, generally grow in moist organic soils in upland rain forests.


Solanum oxycarpum, like all four Mexican and Central American species in the Conicibaccata group, is distinguished by conical fruits, leaves with a somewhat parallel-sided morphology, and narrowly ovate to elliptical leaflets. It is most similar to S. agrimonifolium and S. woodsonii (see discussion under S. woodsonii).

The holotype of S. confusum is Nelson 1319 (GH) but a duplicate at US is S. verrucosum.

Hawkes (1990) placed S. reconditum in synonymy under S. schenckii, but S. reconditum is clearly a synonym of S. oxycarpum.


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. 1995. Phylogenetic relationships of wild potatoes, Solanum series Conicibaccata (sect. Petota). Ph.D. Thesis, University of Wisconsin-Madison.

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

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

Spooner, D.M., R.G. van den Berg, A. Rivera-Peña, P. Velguth, A. del Rio, & A. Salas 2001. Taxonomy of Mexican and Central American members of Solanum series Conicibaccata (sect. Petota). Syst. Bot. 26: 743-756.

Spooner, D.M. & R.J. Hijmans 2001. Potato systematics and germplasm collecting, 1989-2000. Amer. J. Potato Res. 78:237-268; 395.

Spooner, D.M. & K.J. Sytsma 1992. Reexamination of series relationships of Mexican and Central American wild potatoes (Solanum sect. Petota): evidence from chloroplast DNA restriction site variation. Syst. Bot. 17:432-448.

Spooner, D.M., R.G. van den Berg, A. Rodríguez, J. Bamberg, R.J. Hijmans, & S.I. Lara-Cabrera 2004. Wild potatoes (Solanum section Petota; Solanaceae) of North and Central America.
Syst. Bot. Monog. 68: 1-209 + 9 plates.


Chloroplast DNA restriction site data available in: Spooner and Sytsma (1992), Castillo (1995); nuclear data available in Fajardo & Spooner (2011).

Wed, 2013-11-20 11:01 -- sandy
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith