Solanum arcanum is a species of flowering plant in the nightshade family Solanaceae in section Lycopersicon, the tomatoes, endemic to Peru.

Its stem is between 7 and 12 mm (0.3 and 0.5 in) in diameter at its base, often hollow, green, glabrous to variously pubescent with a mixture of simple uniseriate trichomes.

[4] Ovary is globose, glabrous or with a few minute trichomes at the apex; the style being between 0.8 and 1 cm (0.3 and 0.4 in); stigma capitate and green.

Seeds are obovate, narrowly winged at the apex and acute at the base, pale brown, pubescent with hair-like outgrowths of the tegument cell radial walls, which give the surface a silky appearance.

[citation needed] It is found in coastal and inland Andean valleys in northern Peru at elevations 100–2,500 metres (300–8,200 feet).