Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum ×rechei

Citation author: 
Hawkes & Hjert.
Citation: 
in Hawkes, Scott. Pl. Breed. Rec. 146, 171. 1963.
Type: 
Argentina. La Rioja: Dept. Chilecito, Sierra Famatina, Cauchín Viejo, 25 Jan 1928, A. Castellanos s.n. (lectotype, BA, designated by Hawkes & Hjerting 1969; isolectotypes, BA-2 sheets).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M. & A. Clausen
Habit: 
Herbs 25-50 cm tall, erect. Stems 3-5 mm in diameter at base of plant, green to green and purple mottled, winged with wings up to 2 mm, invested with short uniseriate to multicellular non-glandular trichomes; tubers typically placed one at the end of each stolon.
Sympodial structure: 
Sympodial units tri- to plurifoliate, not geminate.
Leaves: 
Leaves odd-pinnate, the blades 12-28 x 2.5-11 cm, green, membranous to chartaceous, pubescent adaxially and abaxially with hairs like those of the stems, usually finely ciliate and denticulate at the margins; lateral leaflet pairs 2-4, often subequal except for the most proximal pair that is greatly reduced in size; most distal lateral leaflets 4.5-9.5 x 2.4-4 cm, elliptic to broadly ovate, the apex acute to acuminate, the base typically oblique; terminal leaflet 6.5-13 x 3.3-8.2 cm, very broadly ovate to broadly elliptic to almost rounded, the apex acute to acuminate, the base shallowly cordate to truncate to cuneate; interjected leaflets 0-5, petiolules up to 10 mm long or more rarely sessile, ovate to orbicular; petioles 2.5-6 cm. Pseudostipules absent or up to 10 mm long, pubescent with hairs like those of the stem.
Inflorescences: 
Inflorescences 3-10 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 13-21 flowers, with all flowers apparently perfect, the axes pubescent with hairs like those of the stem; peduncle 4-19 cm long; pedicels 1.3-2.1 mm long in flower and fruit, spaced 1-10 mm apart, articulated at about the middle.
Flowers: 
Flowers homostylous, 5-merous. Calyx 6-7 mm long, the tube 1-2 mm, the lobes 4-6 mm, long attenuate, the acumens ca. 2.3 mm long, with hairs like those of the stem. Corolla 2-3 cm in diameter, pentagonal, white to white tinged with blue adaxially and abaxially, the tube 1-2 mm long, the acumens ca. 1.3 mm long, the corolla edges flat, not folded dorsally, glabrous adaxially, minutely puberulent abaxially, especially along the midribs, ciliate at the margins, especially at the tips of the corollas. Stamens with the filaments 1-2 mm long; anthers 4-6 mm long, not always well-developed, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 10-11 mm x ca. 1 mm, exceeding stamens by 3-4 mm, straight, glabrous; stigma clavate to capitate.
Fruits: 
Fruit a globose berry, 0.8-1.5 cm in diameter, green, glabrous.
Seeds: 
Seeds from living specimens ovoid and ca. 2 mm long, whitish to greenish in fresh condition and drying brownish, with a thick covering of “hair-like” lateral walls of the testal cells that make the seeds mucilaginous when wet, green-white throughout; testal cells honeycomb-shaped when lateral walls removed by enzyme digestion.
Chromosome number: 

2n = 2x = 24 voucher: Spooner & Clausen 4572 (BAL) (Hijmans, et al. 2007)
2n = 3x = 36 voucher: Spooner & Clausen 4577 (BAL) (Hijmans, et al. 2007)

Distribution: 

Solanum ×rechei is only known from western Argentina (Prov. La Rioja), in generally dry rocky areas in the open or among spiny shrubs or cacti, or as a weed in orchards or the edges of cultivated fields; (1200) 1600-2100 (3950) m in elevation.

Phenology: 
Flowering and fruiting from January to March.
Phylogeny: 

Solanum ×rechei is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, Solanum ×rechei is a member of a very diverse clade related to the cultivated potato. On a higher taxonomic level, it is a member of the informally-named Potato Clade, a group of perhaps 200-300 species that also includes the tomato and its wild relatives (Bohs, 2005).

Commentary: 

Solanum ×rechei is found growing with S. kurtzianum and S. microdontum, and is a natural hybrid between these two species. From S. kurtzianum it can be differentiated by its well developed stem wings, larger terminal leaflet and sometimes less developed anthers. From S. microdontum it can be differentiated by its smaller terminal leaflet, narrower stem wings, and larger number of lateral leaflets.

Both triploid and diploid cytotypes of S. microdontum have been shown to hybridize with S. kurtzianum in the Famatina Mountains in Prov. La Rioja, Argentina. These hybrids were first described as S. rechei (Hawkes, 1963) but it was later shown that S. rechei was an interspecific hybrid that propagates mainly by tubers and is common in disturbed habitats in the Famatina Mountains (Okada and Hawkes, 1978). This hypothesis of a hybrid origin was supported by Clausen and Spooner (1998) on the basis of additive parental-specific single-to low-copy nuclear RFLPs.

References: 

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

Clausen, A.M. & D.M. Spooner 1998. Molecular support for the hybrid origin of the wild potato species Solanum × rechei (Solanum sect. Petota).
Crop Sci. 38: 858-865.

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.

Hijmans, R., T. Gavrilenko, S. Stephenson, J. Bamberg, A. Salas & D.M. Spooner 2007. Geographic and environmental range expansion through polyploidy in wild potatoes (Solanum section Petota).
Global Ecol. Biogeogr. 16: 485-495.

Wed, 2013-11-20 10:57 -- 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