Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum mochiquense

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Citation author: 
Ochoa
Citation: 
Agronomía (Lima) 26: 111. 1959.
Type: 
Peru. La Libertad: Prov. Trujillo, Mount Campana, near Trujillo, 10 Sep 1952, C. Ochoa 1822 (holotype, CUZ [Correll neg. 18, BM000882045, LL, NY, UC1152349]).
Last edited by: 
Spooner, D.M.
Written by: 
Spooner, D.M. & M. Ames
Habit: 
Herbs 0.2-0.8 m tall, erect. Stems 2-9 mm in diameter at base of plant, light green, unwinged or with narrow wings to 2 mm, glabrous; 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 6.6-22 x 4-13.5 cm, dark green adaxially, light green abaxially, coriaceous, glabrous adaxially, glabrous to puberulent abaxially; lateral leaflet pairs 2-7, decreasing in size toward the leaf base, with the terminal leaflet slightly larger than or subequal to the laterals; most distal lateral leaflets 2.2-4.5 x 1.2-2.3 cm, ovate to elliptic, the apex acute, the base typically petiolulate and attenuate to rounded, usually asymmetric with more tissue on the basiscopic side; terminal leaflet 2.8-10.5 x 1.7-6.5 cm, ovate to elliptic, the apex acute to acuminate, the base attenuate; interjected leaflets 0-37, usually sessile, ovate to orbicular; petioles 1-3 cm, glabrous. Pseudostipules 2-12 mm long, glabrous to subglabrous.
Inflorescences: 
Inflorescences 6.8-14.5 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 1-53 flowers, with all flowers apparently perfect, the axes glabrous to glabrescent with white short hairs; peduncle 0.5-5.8 cm long; pedicels 5-41 mm long in flower and fruit, spaced 3-5 mm apart, articulated in the middle to slightly above the middle.
Flowers: 
Flowers homostylous, 5-merous. Calyx 3-7 mm long, the tube 1-3 mm, the lobes 1-4 mm, usually ovate to lanceolate, with linear acumens 1-2 mm long, glabrous to glabrescent with white short hairs. Corolla 2.3-5.9 cm in diameter, pentagonal to rotate, white, the tube 1-2 mm long, the acumens 2-3 mm long, the corolla edges flat, not folded dorsally, glabrous adaxially and abaxially. Stamens with the filaments 1-2 mm long; anthers 6-10 mm long, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 3-10 mm x ca. 1 mm, exceeding stamens by 0.5-8 mm, straight, glabrous; stigma clavate to capitate.
Fruits: 
Fruit a globose berry, 1.1-2.7 cm in diameter, light green with small white dots when ripe, 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: Ochoa & Salas 14870 (CIP) (Hijmans, et al. 2007)

Distribution: 

Solanum mochiquense occurs in Peru (Depts. Ancash, Cajamarca, La Libertad, Lambayeque, Lima and Piura), in two disjunct habitats, in lomas on the coast from 150-800 m in elevation and in dry rocky soils on the mountains from 1170-3000 m.

Phenology: 
Flowering and fruiting on the lomas from August to October, and in the mountains from March-May.
Phylogeny: 

Solanum mochiquense is a member of Solanum sect. Petota Dumort., the tuber-bearing cultivated and wild potatoes. Within sect. Petota, Solanum mochiquense is a member of a distinctive clade of southern Ecuadorian and Peruvian species formerly classified in series Piurana and some other series that frequently possess moniliform tubers and shiny coriaceous leaves, although this species lacks moniliform tubers. 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 mochiquense is a very distinctive wild potato species with its combination of coriaceous and glabrous leaves, which are particularly shiny and dark green. It is most similar to S. cajamarquense, also from Peru, which is a very pubescent plant.

References: 

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.

Taxonomic name: 
Solanum mochiquense (Solanaceae)
Wed, 2013-11-20 11:01 -- sandy
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