Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum ehrenbergii

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Citation author: 
(Bitter) Rydberg
Citation: 
Bull. Torrey Bot. Club 51: 169. 1924.
Type: 
Mexico. without locality, Ehrenberg s.n. (holotype: B, destroyed).-neotype, designated by Spooner et al., 2004: Querétaro: near Querétaro, 20-23 Aug 1906, J. N. Rose & J. S. Rose 11183 (neotype: GH!; isoneotypes: NY!, US-453965! [photo: PTIS!]).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M.
Habit: 
Herbaceous tuber-bearing perennials 0.8 m tall. Stems 2-4 mm in diameter at base of plant.
Sympodial structure: 
Sympodial units typically 3-6-foliate.
Leaves: 
Pseudostipules to 7-20 mm long, lunate. Leaves odd-pinnate, (3-) 5-15 (-30) cm long, 5-8 cm wide, pilose with simple and glandular hairs abaxially and abaxially; petioles 2.5-4.2 cm long; lateral leaflet pairs (1-) 2-3 (-4), the size of the lateral leaflets diminishing abruptly towards the base of the leaf; most distal lateral leaflets 1-10 cm long, 1-5 cm wide, ovate to ovate-lanceolate, apex acute to obtuse, base cordate, rounded, oblique to slightly truncate, sessile to petiolate with petiolules up to 5 mm; terminal leaflet 3-12 cm long, 1.5-6 cm wide, ovate-elliptic to elliptic-lanceolate, apex acute to acuminate, base cordate, rounded, cuneate, or oblique; interjected leaflets 0-2.
Inflorescences: 
Inflorescence a dichasially branched, ebracteate, monochasial or dichasial cyme, 2-3 forked, generally in the distal half of the plant, with 3-20 flowers, all flowers perfect, peduncle 1-11.5 cm long; pedicels 20-30 (-44) mm long, articulate between the proximal ¼ and the distal ¼.
Flowers: 
Flowers with the calyx 5-6 mm long, lobes elliptic, apiculate, acumens 1-2 mm long. Corollas 2-2.5 cm in diameter, stellate, without acumens, edges of corolla flat, not folded dorsally, white with tones of violet on the abaxial side of the lobe tips. Anthers 5-6 mm long, connate, yellow, apically poricidally dehiscent and often maturing to a short introrse apical slit, filaments 1-4 mm long. Ovary with style 10-13 mm long, exceeding stamens by 2.5-4 mm, straight, with stigma globose.
Fruits: 
Fruits 1 cm in diameter, globose, light green throughout.
Seeds: 
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 =24 voucher missing = (Spooner & Hijmans 2001)

Distribution: 

Central Mexico, states of Aguascalientes, Guanajuato, Hidalgo, Jalisco, México, Michoacán, Nayarit, Puebla, Querétaro, San Luis Potosí, Zacatecas, and Distrito Federal, (800) 1450-2500 m; in and about cultivated fields, xerophytic scrublands, tropical deciduous forests, mesquite grasslands, or in areas of oak and pine forests.

Phenology: 
Flowering and fruiting July through October.
Phylogeny: 

Solanum ehrenbergii belongs to the potato clade of Solanum (Bohs, in press). Spooner and Sytsma (1992) placed S. ehrenbergii and all other North and Central American diploids (exclusive of S. bulbocastanum, S. cardiophyllum, and S. verrucosum) in the basal “clade 1” of section Petota based on chloroplast DNA restriction site data. These Mexican diploids were studied by Spooner and Lara-Cabrera (in press, a) with morphological and microsatellite data and by Lara-Cabrera and Spooner (in press b) with AFLP data. Spooner et al. (2004) placed S. ehrenbergii in the Stenophyllidia group which also contains the phenetically similar S. hintonii and S. stenophyllidium. They recognized this as a possibly paraphyletic group of convenience until more data were available on interspecific relationships.

Commentary: 

Solanum ehrenbergii is very similar to S. stenophyllidium. It is distinguished by its ovate-lanceolate to lanceolate leaflets with the base cordate, oblique, or slightly truncate; in S. steonphyllidium the leaflets are linear to linear-lanceolate with an oblique base.

Hawkes (1963) proposed S. ×sambucinum as a hybrid of S. cardiophyllum subsp. ehrenbergii (S. ehrenbergii) and S. pinnatisectum. Solanum ×sambucinum has more numerous lateral leaflets (4-5) than S. ehrenbergii (2-3, rarely 4).

Bitter (1912) proposed a definitive description for Solanum cardiophyllum subsp. ehrenbergii based on a single specimen collected by Ehrenberg in Mexico and then housed at B; this holotype was destroyed. Spooner et al. (2004) agreed with Correll (1962) that S. ehrenbergii is an accepted species. Correll (1962: 262) chose as “lectotype” Rose & Rose 11183 but cited three herbaria (GH, NY, US). Spooner et al. (2004) followed Correll’s suggestion and designated Rose & Rose 11183 at GH as the neotype.

References: 

Lara-Cabrera, S. & D.M. Spooner Taxonomy of Mexican diploid wild potato (Solanum sect. Petota) species: AFLP data.
Plant Syst. Evol.

Lara-Cabrera, S. & D.M. Spooner Taxonomy of Mexican diploid wild potato (Solanum sect. Petota) species: morphological and microsatellite data.
Monogr. Syst. Bot., Missouri Bot. Gard.

Bitter, G. 1912. Solana nova vel minus cognita, V, VI, IX, X, XI.
Repert. Spec. Nov. Regni Veg. 11: 349-394, 431-473, 12: 1-10, 49-90, 136-162.

Correll, D.S. 1962. The potato and its wild relatives.
Contr. Texas Res. Found., Bot. Stud. 4: 1-606.

Hawkes, J.G. 1963. A revision of the tuber-bearing Solanums. II.
Scott. Pl. Breed. Sta. Rec. 1963: 76-181.

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

Lara-Cabrera, S.I. 2001. Taxonomy of Mexican diploid wild potato (Solanum sect. Petota) species: a morphological and molecular study.
Ph.D. Thesis, Plant Breeding and Plant Genetics Program, University of Wisconsin-Madison.

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.

Genetics: 

Chloroplast DNA restriction site data available in: Spooner and Sytsma (1992). AFLP, morphological, and microsatellite data listed in: Lara-Cabrera (2001).

Taxonomic name: 
Solanum ehrenbergii (Solanaceae)
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