Lycopersicon group (Red/orange/yellow fruited tomatoes)

Solanum lycopersicon (Domestic tomato)

Lycopersicon cerasiforme
Lycopersicon esculentum
Large fruits are typically red. Small flowers. Straight anther cone. Intergrades with S pimpinellifolium. Fully cross-compatible with other members of the Lycopersicon group. Self-compatible, sometimes with flowers that facilitate crossing. More dependent on moisture than other species.

Solanum cheesmaniae (Galapagos tomato)

Lycopersicon peruvianum var. parviflorum
Small fruits yellow or orange. Regular-leaved. Small leaves, and plants. Small flowers. Straight anther cone. Stigma not exposed. Intergrades with S galapagense. Fully cross-compatible with other members of the Lycopersicon group. Strongly selfing. Endemic to all-elevations in the Galapagos Islands.

Solanum galapagense

Lycopersicon cheesmaniae f. minor
Very small fruits yellow or orange. Carrot-leaved. Bushy growth habit. Small flowers. Straight anther cone. Stigma not exposed. Intergrades with S cheesmaniae. Fully cross-compatible with other members of the Lycopersicon group. Strongly selfing. Endemic to low-elevation in the Galapagos Islands.

Solanum pimpinellifolium (Current tomato)

Lycopersicon esculentum ssp. intermedium
Lycopersicon esculentum ssp. pimpinellifolium
Small fruits are red. Regular-leaved. Small leaves, and plants. Small flowers. Deeply lobed petals are diagnostic for this species. Straight anther cone. Stigma exposed. Intergrades with S lycopersicum. Fully cross-compatible with other members of the Lycopersicon group. Self-compatible with flowers that facilitate crossing. Riparian adapted at low elevations in southern Ecuador and Peru.

Arcanum group (Mysterious green-fruited tomatoes)

This group intergrades with each other. Hard to tell them apart based on physical characteristics.

Solanum arcanum

Lycopersicon peruvianum var. humifusum
Fruits green with dark green stripes. Short fuzzy hairs on fruits. Simplified highly-serrated regular-leaf. Extremely variable species. Large flowers. Flower cluster unbranched. Straight anther cone. Exerted stigma. Intergrades with S chmielewskii and S neorickii. Usually self-incompatible. Dry habitat adapted. Some populations adapted to Lomas habitat. Low elevation near the coast and in river valleys.

Solanum chmielewskii

Lycopersicon chmielewskii
Fruits green with dark green stripes. Simplified serrated regular leaf. Intergrades with S arcanum and S neorickii. Large flowers. Flower cluster unbranched. Straight anther cone. Exerted stigma. Self-compatible with flowers that facilitate crossing. Dry habitat adapted. High elevations in south-central Peru to northern Bolivia.

Solanum neorickii

Lycopersicon parviflorum
Fruits green with dark green stripes. Simplified regular-leaf. Small dull flowers. Stigma not exposed. Flower cluster unbranched. Intergrades with S arcanum and S chmielewskii. Self-compatible. Strongly selfing. Dry habitat adapted. High elevations in southern Ecuador to south-central Peru. Descended from Solanum chmielewskii.

Eriopersicon group (Hairy green fruited tomatoes)

Solanum chilense

Lycopersicon peruvianum ssp. Puberulum
Fruits green to whitish-green with purple stripes. Fern-leaved. Stems and leaves densely hairy. Foliage appearing grayish to white. Large flowers. Flower petals have a dark medial stripe. Anther cone straight. Stigma exerted. Branched flower clusters. Coastal areas southern Peru and northern Chile. Intergrades with S. huaylasense. Self-incompatible. Super dry river bed habitat and lomas adapted. Southern Peru to northern Chile. Low to mid-elevations.

Solanum corneliomulleri

Lycopersicon glandulosum
Fruits hairy, green with dark green or purple stripes, and sometimes purple blushing. Fractal leaf pattern. Strongly toothed leaflets. Branched flower cluster. A mixture of hair types on foliage. Large flowers. Anther cone strongly curved. Branched flower clusters. Mature fruits densely covered in long soft hairs. Intergrades with S peruvianum. Usually self-incompatible. Dry habitat adapted. Mid to high elevations. Central to southern Peru.

Solanum habrochaites (Woolly Tomato)

Lycopersicon hirsutum
Fruits green with dark green stripes. Long hairs on fruits. Slightly serrated leaflets attached only to main leaf-stem. Leaflet size alternates: large, tiny, medium, tiny, large. Large flowers. Petals shallowly lobed. Straight anther cone. Exerted stigma. Usually self-incompatible, with some self-compatible populations at the extreme edges of range. Easily used as a pollen donor to domestic tomatoes. Branched flower clusters. The largest plants among the wild tomato species. Grows in a wide variety of high-elevation forest habitats, including lomas. Central Ecuador to central Peru.

Solanum huaylasense

Fruits green with dark green stripes. Fractal leaf pattern. Wispy carrot-leaved. Leaflets serrated. Leaves appearing green to bright green. Leaves largely free of hairs. Large flower petals uniformly colored. Anther cone straight or strongly curved. Branched flower clusters. Intergrades with S. Chilense. Usually self-incompatible. Dry habitat adapted. Endemic near Callejón de Huaylas in Peru.

Solanum peruvianum (Peruvian nightshade)

Lycopersicon glandulosum
Fruits green to greenish-white often with purple blushing. Large flowers. Anther cone curved or strongly curved. Branched flower clusters. Leaves and stems velvety. Intergrades with S corneliomulleri. Usually self-incompatible. Adapted to a wide range of habitats including lomas. Southern Peru to northern Chile. Low to mid-elevations.

Neolycopersicon group (New green-fruited tomato)

Solanum pennellii

Dark green hairy fruits. Short hairs on fruits. Round leaflets and an anther cylinder (instead of an anther cone) are the traits that distinguish S pennellii from all other species. Large flowers with connected petals. Exerted stigma. Strongly bent style. Usually self-incompatible, with some self-compatible populations at the extreme edges of the range. Easily used as a pollen donor to domestic tomatoes. Strongly lomas adapted – the poor root system. Northern Peru to northern Chile. Low to mid-level elevations.

References:

1. https://en.wikipedia.org/wiki/Lycopersicon
2. Peralta, Iris E.; Knapp, Sandra; Spooner, David M. (2005). “New Species of Wild Tomatoes (Solanum Section Lycopersicon: Solanaceae) from Northern Peru”. Systematic Botany. 30 (2): 424–434. doi:10.1600/0363644054223657. ISSN 0363-6445. S2CID 86254917.
3. Iris E. Peralta, David M. Spooner, Sandra Knapp: Taxonomy of Wild Tomatoes and Their Relatives (.. Solanum sect Lycopersicoides, Juglandifolia sect, sect Lycopersicon, Solanaceae.). Systematic Botany Monographs, Volume 84, The American Society of Plant taxonomists, June 2008, ISBN 978-0-912861-84-5
4. Iris Edith Peralta & David M. Spooner (2000), KURTZIANA, Classification of wild tomatoes: a review Torno 28 (I): 45-54.