Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum vernei

Citation author: 
Bitter & Wittm.
Citation: 
Bot. Jahrb. Syst. 50, Beibl. 550. 1914.
Type: 
Argentina. Tucumán: Dept. Tafí, La Ciénaga, 10-17 Jan 1874, G.H.E.W. Hieronymus & P.G. Lorentz 708 (holotype, B, destroyed [F neg. 2794, F-621153, G, NY]; lectotype, CORD, designated by Hawkes and Hjerting, 1969: 358; isotype, GOET [Correll neg. 285, BM000881678, LL, NY]).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M. & A. Clausen
Habit: 
Herbs 0.4-1.5 m tall, erect. Stems 3-8 mm in diameter at base of plant, green to deep purple to mottled green and purple, unwinged or with wings to 1.5 mm wide, subglabrous to short pubescent, sometimes densely so; tubers typically borne singly at the end of each stolon.
Sympodial structure: 
Sympodial units tri- to plurifoliate, not geminate.
Leaves: 
Leaves odd-pinnate, the blades 9-29 x 8-17 cm, green, membranous to chartaceous, sparsely to densely pubescent adaxially, densely pubescent to often canescent abaxially; lateral leaflet pairs 3-4, often subequal except for the most proximal 1 or 2 pairs that are greatly reduced in size; most distal lateral leaflets 5-11 x 2.3-4.8 cm, elliptic to broadly ovate, the apex acute to acuminate, rarely obtuse, the base typically oblique on the basiscopic side and with leaf tissue sometimes decurrent on the petiole, sometimes cuneate to rounded, petiolule sessile to subsessile or up to 10 mm long, typically with 0 or rarely with up to 2 tertiary leaflets on the petiolule; terminal leaflet 4.5-14.5 x 2-7 cm, frequently with 1-4 small paired or unpaired tertiary leaflets on the petiolule, ovate to elliptic, the apex acute to acuminate, the base typically attenuate to acute, or more rarely cordate; interjected leaflets 2-14, sessile to short petiolulate, ovate to orbicular; petioles 0.5-3.5 cm, pubescent with hairs like the stem. Pseudostipules 4-17 mm long, pubescent with hairs like those of the stem.
Inflorescences: 
Inflorescences 4-9 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 9-21 flowers, with all flowers apparently perfect, the axes pubescent with hairs like those of the stem; peduncle 2.3-11.5 cm long; pedicels 1.2-2.8 mm long in flower and fruit, spaced 1-10 mm apart, articulated at or slightly above the middle.
Flowers: 
Flowers homostylous, 5-merous. Calyx 3.6-5 mm long, the tube 1-2 mm, the lobes 1.6-4 mm, long attenuate to apiculate, the acumens 1-2 mm long, with hairs like those of the stem. Corolla 2-3.5 cm in diameter, pentagonal to rotate, violet-purple or light violet, sometimes darker in the rays adaxially and abaxially, the tube 1-2 mm long, the acumens 2-4 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, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 8-10 mm x ca. 1 mm, exceeding stamens by 2-4.5 mm, straight, glabrous; stigma clavate to capitate.
Fruits: 
Fruit a globose berry, 1.4-2 cm in diameter, green when ripe, often with scattered white dots, 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: Okada 4477 (BAL) (Hijmans, et al. 2007)

Distribution: 

Solanum vernei occurs in northern Argentina (Provs. Jujuy, Salta, Tucumán and Catamarca), in steep grassy mountain slopes, under bushes, growing in the sun but also in shaded valleys, in rich humid soil, at the edge of cultivated fields, along ditches; 2270-3600 m in elevation.

Phenology: 
Flowering and fruiting from December to April.
Phylogeny: 

Solanum vernei is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, Solanum vernei 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: 

Hawkes and Hjerting (1969) distinguished subsp. vernei from subsp. ballsii by lateral leaflet characters, with subsp. vernei having the lateral leaflets (except the upper pair) clearly petiolulate, with the apex markedly acuminate and the base gently rounded, and subsp. ballsii with all leaflets sessile or very shortly petiolulate, the leaflet apex obtuse to acute or barely acuminate, and the base markedly auriculate on the basiscopic side. Subsp. vernei is found in the southern distribution of the species range in southern Salta Province through Tucumán and Catamarca, with subsp. ballsii distributed from northern Salta Province just south of the border with Bolivia, south through Prov. Jujuy. They mapped “intermediate forms” in the intersecting areas in Salta Province (Hawkes and Hjerting 1969, Fig. 11). We examined 30 randomly chosen accessions from throughout this distribution area (except the “intermediate area” in Salta Province) from north to south and found all of these characters to vary throughout the range of S. vernei. Therefore, we do not recognize subspecific entities in S. vernei.

References: 

Hawkes, J.G. & J.P. Hjerting 1969. The potatoes of Argentina, Brazil, Paraguay and Uruguay: a biosystematic study.
Oxford Univ. Press, Oxford, UK.

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 11:04 -- sandy
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