Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum hougasii

Citation author: 
D. S. Correll
Madroño 14: 236. 1958.
Cultivated from MEXICO. Michoacán: about base of large trees on edge of balsam cloud forest, about 7 miles above Opopeo, 13 Nov 1947, D. S. Correll 14253 (holotype: NA-14253! [Correll neg. 864: F!, GH!, K!, LL!, NY!, US!]; isotypes: IBUG!, MEXU!).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M.
Herbaceous tuber-bearing perennials up to 0.75 m tall. Stems 3-5 mm in diameter at base of plant.
Sympodial structure: 
Sympodial units typically 3-6-foliate.
Pseudostipules to 3-8 mm long, lunate. Leaves odd-pinnate, 10-24 cm long, 7-15 cm wide, strigose, puberulent or pubescent adaxially and abaxially; petioles 2-6 cm long; lateral leaflet pairs 3-4, the first two pairs often equal or only gradually diminishing in size towards the base of the leaf; most distal lateral leaflets 3.8-7 cm long, 2-4 cm wide, medium to broadly elliptical, apex acute to acuminate, base oblique, cuneate, sessile, or with petiolules up to 10 mm long, rarely decurrent on the rachis; terminal leaflet 4-8 cm long, 1.5-2.9 cm wide, broadly elliptical, apex acute to acuminate, base cuneate; interjected leaflets 4-18.
Inflorescence a dichasially branched, ebracteate, monochasial or dichasial cyme, 2-3 forked, generally in the distal half of the plant, with 9-19 flowers, all flowers perfect, peduncle 2-9.3 cm long; pedicels 11-23 mm long, articulate between the proximal ¼ and the distal ¼.
Flowers with the calyx up to 5-7 mm long, lobes attenuate, acumens 1-2 mm long. Corollas 2.4-2.8 cm in diameter, rotate, acumens 2 cm, edges of corolla flat, not folded dorsally, white throughout or white with purple interpetalar tissue. Anthers 4.5-5.5 mm long, connate, yellow, apically poricidally dehiscent and often maturing to a short introrse apical slit, filaments 1-4 mm long. Ovary with style 8-10 mm long, exceeding stamens by 2.5-4 mm, straight, with stigma globose.
Fruits 1.2-2 cm in diameter, globose, medium green with white spots.
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)


Eastern and central Mexico, states of Colima, Guerrero, Jalisco, Michoacán, 1600-3135 m; at edges of cultivated fields, roadsides, grasslands, in areas of alder and fir and pine and oak forests.

Flowering and fruiting August through December.

Solanum hougasii belongs to the potato clade of Solanum (Bohs, in press). Spooner and Sytsma (1992) placed S. hougasii and all other North and Central American members of the Iopetala group (S. guerreroense, 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 is shared with the North and Central American wild potato species S. demissum that Spooner et al. (2004) placed in the Acaulia group. 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 hougasii is especially similar to S. guerreroense and S. iopetalum (Spooner et al.1995), but differs in the shape of the fruit; Solanum hougasii has globose fruits, and S. iopetalum has ovoid to conical fruits. Because some herbarium specimens of all three of these species lack well-preserved flowers and fruits, this treatment may have misidentified some of them.

Some specimens may superficially appear as type material but were collected at a later date. Those at LL and PTIS are cultivated specimens, but were prepared in1953 and are labeled Correll 14253a or 14253b. A specimen at C bears a collection number Correll 14253 but was collected 1987.


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. & 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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