Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum ×sambucinum

Citation author: 
Rydberg
Citation: 
Bull. Torrey Bot. Club 51: 169. 1924.
Type: 
Mexico. Querétaro: stony hillsides near San Juan del Río, 18 Aug 1905, J. N. Rose, J. H. Painter, & J. S. Rose 9586 (holotype: US-453076!, [Correll neg. 139: BM!, F!, GH!, K!, LL!, NY!, UC!, US!; drawing: K!]).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M.
Habit: 
Herbaceous tuber-bearing perennials 0.3-0.8 m tall. Stems 4-6 mm in diameter at base of plant.
Sympodial structure: 
Sympodial units typically 3-6-foliate.
Leaves: 
Pseudostipules 8-10 mm long, lunate. Leaves odd-pinnate, 10-16 cm long, 4-12 cm wide, puberulent or glabrous adaxially and abaxially; petioles 1-3.5 cm long; lateral leaflet pairs 4-5, the second most distal lateral leaflets larger than the most distal, then the size of the lateral leaflets diminishing gradually towards the base of the leaf; most distal lateral leaflets 3-5.5 cm long, 1-2 cm wide, lanceolate to elliptic-lanceolate, apex acute, base oblique, sessile, decurrent on the rachis; terminal leaflet 4-7 cm long, 1-2 cm wide, lanceolate to elliptic-lanceolate, apex acute to acuminate, base cuneate; interjected leaflets absent.
Inflorescences: 
Inflorescence a dichasially branched, ebracteate, monochasial or dichasial cyme, 2-3 forked, generally in the distal half of the plant, with 12-17 flowers, all flowers perfect, peduncle 2-4.5 cm long; pedicels 15-25 mm long, articulate between the proximal ¼ and the distal ¼.
Flowers: 
Flowers with the calyx up to 5 mm long, lobes oblong or elliptic, mucronate, acumens 0.5-1 mm long. Corollas 2.5 cm in diameter, stellate, without acumens, edges of corolla flat, not folded dorsally, white. Anthers 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 10-11 mm long, exceeding stamens by 2-3 mm, straight, with stigma globose.
Fruits: 
Fruits 0.8 cm in diameter, globose, 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: 

Mexico (Guanajuato and Querétaro), 1720-2200 m; in and at margin of cultivated fields, tropical deciduous forests, fencerows, rock piles, among thorny bushes, mesquite grasslands.

Phenology: 
Flowering and fruiting August through October.
Phylogeny: 

Solanum ×sambucinum belongs to the potato clade of Solanum (Bohs, in press). Hawkes (1963) proposed S. ×sambucinum as a hybrid of S. cardiophyllum subsp. ehrenbergii (=S. ehrenbergii) and S. pinnatisectum; he considered overlap of parental ranges, intermediate morphology, and morphological segregation of F1 offspring to the parental types when grown from seed (see Fig. 51 of Spooner et al. 2004). Hawkes and Lester (1968) quantified leaf shape and immunological differences between these three taxa to further support their hypothesis. Solanum ×sambucinum has fewer lateral leaflets (4-5) than S. pinnatisectum (6-8); S. ×sambucinum has lunate pseudostipules while S. pinnatisectum pinnatifid pseudostipules, and S. ×sambucinum has lanceolate leaflets while S. pinnatisectum has linear-lanceolate leaflets.

References: 

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

Hawkes, J.G., & R.N. Lester 1968. Immunological studies on the tuber-bearing Solanums III. Variability within S. bulbocastanum and its hybrids with species in series Pinnatisecta.
Ann. Bot. (Oxford) 32: 165-186.

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).

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