Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum guerreroense

Citation author: 
D. S. Correll
Agric. Monogr. U.S.D.A. 11: 65, figs. 43, 44. 1952.
Cultivated and harvested 9-11 Aug 1949 (from tubers collected on 27 Dec 1947 in Mexico. Guerrero: in pine oak forest on summit of mountain above Chilpancingo, to the north, from an unvouchered collection referred to as Correll 14410) at Sturgeon Bay, Wisconsin, D. S. Correll 14410a (holotype: NA!, [Correll neg. 30: BM!, F!, K!, LL!, NY!, UC!, US!]; isotypes: MEXU!, PTIS! [Correll neg. 66: BM!, F!, K!, LL!, US!]).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M.
Herbaceous tuber-bearing perennials 0.25 m tall. Stems 4 mm in diameter at base of plant.
Sympodial structure: 
Sympodial units typically 3-6-foliate.
Pseudostipules to 6-8 mm long, lunate. Leaves odd-pinnate, 14-44 cm long, 11-13 cm wide, pubescent, strigose to puberulent adaxially and abaxially; petioles 1-3 cm long; lateral leaflet pairs 4-5, the first two pairs often equal or only gradually diminishing in size towards the base of the leaf; most distal lateral leaflets 5-7 cm long, 2-4 cm wide, ovate to broadly elliptical, apex acute to acuminate, base oblique, cuneate to cordate, sessile; terminal leaflet 5-7.5 cm long, 3.5-4.2 cm wide, broadly elliptical, apex acute to acuminate, base cuneate to truncate; interjected leaflets 8-19.
Inflorescence a dichasially branched, ebracteate, monochasial or dichasial cyme, 2-3 forked, generally in the distal half of the plant, with 8-14 flowers, all flowers perfect, peduncle up to 3.4 cm long; pedicels 11-23 mm long, articulate between the proximal ¼ and the distal ¼.
Flowers with the calyx up to 4 mm long, lobes atenuate, acumens 1-2 mm long. Corollas 2.6 cm in diameter, rotate, acumens up to 2 mm long, edges of corolla flat, not folded dorsally, light violet adaxially, darker violet abaxially. Anthers 6 mm long, connate, yellow, apically poricidally dehiscent and often maturing to a short introrse apical slit, filaments 1-4 mm long. Ovary with style up to 9 mm long, not exceeding stamens, straight, with stigma globose.
Fruits up to 3 cm in long, conical, medium 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 =72 voucher missing = (Spooner & Hijmans 2001)


Known only from the type in Guerrero, Mexico; elevation not recorded; in pine-oak forests.

The sole type collection was made with mature fruits in late December, but considering other members of the Iopetala group S. guerreroense may flower and fruit July through December.

Solanum guerreroense belongs to the potato clade of Solanum (Bohs, in press). Spooner and Sytsma (1992) placed S. guerreroense and all other North and Central American members of the Iopetala group (S. hougasii, S. iopetalum, S. schenckii) in a terminal clade based on chloroplast DNA restriction site data. Included here are four polysomic polyploid 6x(4EBN) species; this ploidy/EBN shared in North and Central America only with S. demissum. The members of the Iopetala group are very similar to each other and to one of their putative genome contributors, S. verrucosum (diploid). The members of the Iopetala group also are morphologically similar to S. stoloniferum 4x(2ENB), but are separated from it by strong EBN-based crossability barriers. There are no clear morphological characters uniting members of this group, their parental origins are unknown and, like other polyploids, they could have multiple origins. These factors make them difficult to classify in any phylogenetic classification and frustratingly difficult to identify without well-preserved complete flowering and fruiting specimens. We define the Iopetala group largely based on the 6x(4EBN) crossability.


Solanum guerreroense is known only from the type, a specimen grown from tubers collected in the wild from Mexico. Other herbarium specimens bearing this collection number at K and LL were collected later and are therefore not considered type material. Searches for S. guerreroense in 1988 (Spooner et al. 1991) and 1997 (Spooner et al. 2000) at the locality in Guerrero from which Correll obtained the tubers were unsuccessful. The type was collected in mature fruit in December; indicating S. guerreroense may flower and fruit from July to December, like other members of the Iopetala group.

Correll (1952) described S. guerreroense as a low-growing plant (similar to some populations of S. demissum), with white corollas (like S. hougasii), and with conical fruits (like S. iopetalum). He cited two gatherings of this species, Correll 14410 (the source of the tubers in Guerrero from which the type was grown), and Hinton 11929 from Michoacán). Correll (1952) identified another collection, Correll 14342, as S. verrucosum var. spectabilis (=S. hougasii) that was later identified in the US Potato genebank as S. guerreroense. The morphological study of Spooner et al. (1995) showed material identified in genebanks as S. guerreroense, S. hougasii, and S. iopetalum (including S. brachycarpum), to be very difficult to separate into three taxa, but Correll 14342 clustered with other populations of S. hougasii.

Solanum guerreroense is very similar to both S. iopetalum (with fewer interstitial and lateral leaflets), and S. hougasii (with globose fruits) (Spooner et al. 1995). Spooner et al. (2004) identified Correll’s (1952) paratype Hinton 11929 as S. hougasii. Solanum guerreroense may be a highly rare and endemic species very similar to and possibly conspecific with S. iopetalum. Lack of comparative material from the type locality confounds this decision.


Correll, D.S. 1952. Section Tuberarium of the genus Solanum of North America and Central America.
U.S.D.A. Agric. Monogr. 11: 1-243.

Spooner, D.M., J. Bamberg, J.P. Hjerting, & J. Gómez 1991. Mexico, 1988 potato germplasm collecting expedition and utility of the Mexican potato species.
Amer. Potato J. 68:29-43.

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, & J.B. Bamberg 1995. Examination of species boundaries of Solanum series Demissa and potentially related species in series Acaulia and series Tuberosa (sect. Petota).
Syst. Bot. 20: 295-314.

Spooner, D.M., A. Rivera-Peña, R.G. van den Berg & K. Schüler 2000. Potato germplasm collecting expedition to Mexico in 1997: taxonomy and new germplasm resources.
Amer. J. Potato Res. 77: 261-270.

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., 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.

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.


Chloroplast DNA restriction site data available in: Spooner and Sytsma (1992).

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