Solanum arcanum is a species of nightshade, commonly called the "wild tomato," endemic to Peru.[1]
The wild tomato is a perennial[2] plant, woody at the base, being up to 1m (03feet) or more in diameter and up to 1m tall. Its stem is between 7mm12mm in diameter at its base, often hollow, green, glabrous to variously pubescent with a mixture of simple uniseriate trichomes.
Its sympodial units are 2-foliate; internodes being between 2cmand6cmcm (01inchesand02inchescm). Its leaves are interrupted imparipinnate, green to pale beneath, glabrous to sparsely short pubescent with a mixture of simple uniseriate trichomes, some populations lacking trichomes. The petiolule is between 0.5cmand1cmcm (00.2inchesand00inchescm).
Inflorescences are between 6cmand20cmcm (02inchesand10inchescm) in size, simple, with 5–20 flowers, ebracteate or nearly all the nodes bracteate; peduncle between 3.5cmand10cmcm (01.4inchesand00inchescm), glabrous and minutely glandular to densely velvety pubescent with intermixed longer patent trichomes like those of the stems. The pedicels are between 1.1cmand1.7cmcm (00.4inchesand00.7inchescm), articulated at the middle or in the distal half. Buds are conical, straight, approximately half way exerted from the calyx. Flowers with the calyx tube are minute, the lobes lanceolate; corolla is between 1.8cmand2cmcm (00.7inchesand01inchescm), pentagonal and yellow.
Ovary is globose, glabrous or with a few minute trichomes at the apex; the style being between 0.8cmand1cmcm (00.3inchesand00inchescm); stigma capitate and green. The fruit is between 1cmand1.4cmcm (00inchesand00.6inchescm) in diameter, globose and green with a dark green stripe around it that may change to purple at maturity. 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. Chromosome number: n=12.
It is found in coastal and inland Andean valleys in northern Peru (between 100mand2500mm (300feetand8,200feetm)).