Citation:
Agronomía (Lima) 26(4): 314. 1959.
Type:
Peru. Cajamarca: Prov. Cajamarca, Lanchi, near Chiquidén, ascending from San Juan to El Paso del Gavilán, 2600 m, 17 May 1952, Ochoa 1490 (holotype, CUZ [Correll neg. 19, BM000881775, F-1604412, NY, UC1152208]; isotypes, CUZ [Correll neg. 20, BM000881775, F-1604414, NY, UC1152208], F-2190630 [F neg. 70879], GH, K-2 sheets, LL [Correll neg. 859, BM000881774, UC1152208]).
Habit:
Herbs 0.25-0.94 m tall, erect. Stems 2-9 mm in diameter at base of plant, brown to yellow, sometimes winged, the wings 0-0.34 cm wide, densely pubescent with whitish hairs; tubers typically moniliform (multiple tubers arranged along the stolon like beads on a necklace).
Sympodial structure:
Sympodial units tri- to plurifoliate, not geminate.
Leaves:
Leaves odd-pinnate, the blades 6.6-18 x 5.6-13.1 cm, dark green to yellowish, coriaceous, densely pubescent adaxially and abaxially with very short white hairs; lateral leaflet pairs 2-4, decreasing in size toward the leaf base, with the terminal leaflet subequal to or larger than the lateral leaflets; most distal lateral leaflets 2.7-6.9 x 1.4-3.5 cm, ovate to oblanceolate, the apex acute to acuminate, the base typically sessile and attenuate to rounded, asymmetric, with more tissue on the basiscopic side of leaflet; terminal leaflet 3.8-8.5 x 2-5.3 cm, ovate, the apex acute to acuminate, the base attenuate; interjected leaflets 0-38, sessile, ovate to orbicular; petioles 1-2 cm, densely pubescent with whitish simple hairs. Pseudostipules 0.4-5 mm long, densely pubescent as the stems.
Inflorescences:
Inflorescences 3.2-17.5 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 10-60 flowers, with all flowers apparently perfect, the axes densely pubescent as the rest of the plant; peduncle 2.5-13.5 cm long; pedicels 16-54 mm long in flower and fruit, spaced 1-10 mm apart, articulated high in the distal half.
Flowers:
Flowers homostylous, 5-merous. Calyx 7-9 mm long, the tube 1-3 mm, the lobes 3-4 mm, linear, the acumens 1-2 mm long, densely pubescent as the stems. Corolla 2.6-4.8 cm in diameter, pentagonal to rotate, white, the tube 1-2 mm long, the acumens 0.5-1.2 mm long, the corolla edges flat, not folded dorsally, sub-glabrous adaxially with hairs on the margins of the petal acumens, pubescent abaxially. Stamens with the filaments 1-2 mm long; anthers 4-8 mm long, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 6-13 mm x ca. 1 mm, exceeding stamens by 2-6 mm, straight, glabrous; stigma clavate to capitate.
Fruits:
Fruit a globose berry, 1.2-2.1 cm in diameter, light green, sometimes with purple stripes 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.
Phenology:
Flowering and fruiting from March to May.
Solanum cajamarquense is a very distinct species. It is extremely pubescent, with the terminal leaflet distinctly ovate and is unlikely to be confused with any other wild potato species.