Solanum sitiens
Citation:
Revista Chilena Hist. Nat. 33: 25. 1930.
Type:
Chile. Antofagasta: near Calama, ca. 3300 m, 7 Sep 1919, Moore & Abbott s.n. (holotype, US-1038130).
Written by:
Peralta, I.E., S. Knapp & D.M. Spooner
Habit:
Small, erect to somewhat sprawling shrubs, woody at the base, to 0.7 m tall, 30-40 cm diameter at base, pleasant smelling (fide Moore & Abbott s.n.). Stems 7-10 mm diameter at the base, bright green, glabrous to moderately pubescent with simple uniseriate glandular trichomes with 4-celled heads and sparser simple uniseriate eglandular 4-6-celled trichomes to 0.5 mm long, glabrescent in age.
Sympodial structure:
Sympodial units 5-plurifoliate; internodes (1-) 2-4 cm long.
Leaves:
Leaves interrupted imparipinnate or pinnatifid, the divisions not clear-cut, 1.9-7 cm long, 1-5 cm wide, thick and fleshy, bright green, pubescent like the stems with sparse simple uniseriate trichomes, occasionally almost completely glabrous, glabrescent in age, the adaxial surface glandular to glabrous with a few simple uniseriate trichomes, the abaxial surface more pubescent, especially along the veins; primary leaflets 3-4 pairs, not well differentiated from the axis, narrowly elliptic, the base decurrent, the margins deeply once-lobed halfway to the rachis, the apex acute; terminal leaflet usually sessile and not well differentiated from the most distal lateral leaflets, 0.5-2.5 cm long, 0.3-2 cm wide, the base decurrent onto the rest of the leaf; secondary leaflets absent; tertiary leaflets absent; interjected leaflets 0-2(-5), small lobes along the spaces between the lateral leaflets, orbicular, 0.1-0.3 cm in diameter; petiole 0.2-1 cm long; pseudostipules present.
Inflorescences:
Inflorescences 3.5-9 cm long, 2-3 times branched, with 10-50 flowers, bracteate, the bracts 0.3-0.5 cm long, 0.2-0.4 cm wide, smaller towards the tip of the inflorescence, peduncle 1-5 cm long, glabrous to sparsely pubescent like the stems. Pedicels 0.7-1.1 cm long, articulated in the distal 1/3-1/2. Buds ca. 1 cm long, 0.4-0.5 cm wide, ellipsoid, with the corolla more than halfway exserted form the calyx lobes just before anthesis.
Flowers:
Flowers with the calyx tube ca. 0.25 cm long, the lobes 0.4-0.5 cm long, 0.1-0.15 cm wide, narrowly deltate, the apex acuminate, sparsely pubescent with simple uniseriate trichomes and minute glandular trichomes like those of the stems; corolla 1.8-2.1 cm in diameter, rotate, yellow, finely pubescent abaxially, the trichomes more abundant at the tips, the tube 0.6-0.7 cm long, the lobes 0.5-0.6 cm long, 0.5-0.7(-0.9) cm wide, spreading at anthesis; staminal column not present, the stamens free, straight, the filaments 0.5-0.6 mm long, the anthers 0.45-0.5 cm long, the sterile apical appendage absent; ovary conical, glabrous; style 1-1.2 cm long, ca. 0.5 mm in diameter, densely fine white pubescent in the proximal half, curved and exserted 2-3 mm beyond the anthers; stigma bifid, green (occasionally appearing large capitate to clavate in dry material).
Fruits:
Fruit 1.1-1.3 cm in diameter, globose, 2-locular, pale yellowish when ripe, shiny and glabrous, becoming dry and papery with age; fruiting pedicels 1-1.7 cm long, straight; calyx lobes in fruit 0.4-0.5 cm long, 0.1-0.15(-0.25) cm wide, not markedly elongating, spreading.
Seeds:
Seeds 2.2-2.8 mm long. 1.7-2.3 mm wide, 0.5-0.7 mm thick, obovate, pale brown, pubescent with hair-like outgrowths of the lateral testa cell walls, which give a silky appearance to the surface, narrowly winged at the apex and acute at the base.
Chromosome number:
2n = ploidy missing =24 voucher missing = (Correll 1964)
Distribution:
On the W Andean slopes in N Chile from 2350-3500 m, on rocky hillsides and dry quebradas.
Phenology:
Solanum sitiens appears to have two flowering peaks, one between January and May and the other in November (Smith & Peralta 2002).
Phylogeny:
Solanum sitiens is a member of the Potato clade (sensu Weese & Bohs, 2007); within the tomatoes and wild relatives it is a member of section Lycopersicoides.
References:
Smith, S., & I.E. Peralta 2002. Ecogeographic surveys as tools for analyzing potential reproductive isolating mechanisms: an example using Solanum juglandifolium Dunal, S. ochranthum Dunal, S. lycopersicoides Dunal, and S. sitiens I.M. Johnston.
Taxon 51: 341-349.
Solanum sitiens is sister to S. lycopersicoides, differences between can be seen in the key and in the discussion of S. lycopersicoides above. Solanum sitiens has more dissected leaves than S. lycopersicoides and a yellowish, rather than purple or black, fruit. Solanum sitiens is a small shrub that apparently holds onto its fruits for a long time, where they turn papery and dry. Flowering in S. sitiens appears to peak in November with a minor flowering episode in January to May, but the number of specimens collected is very small and this bimodality may be merely a collecting artifact.
Solanum sitiens and S. lycopersicoides are both endemics of the western Andean deserts of Peru and Chile, and adapted to extremely arid conditions. Based on the paucity of collections and the current knowledge about population distribution, and habitat threat due to cattle ranching in their native distributions, both these species can be considered vulnerable and a priority for in situ conservation.