Solanum huaylasense
Citation:
Syst. Bot. 30: 429. 2005.
Type:
Peru. Ancash: trail to cave across Río Santa from Mancos, 9 Apr 1970, Smith & Blas 4889 (holotype, USM; isotypes, F, US).
Written by:
Peralta, I.E., S. Knapp & D.M. Spooner
Habit:
Sprawling perennial herbs, woody at the base, to 1 m tall, to 1 m in diameter. Stem 7-10 mm in diameter at base, green, minutely puberulent with simple, uniseriate, stiff 1-2-celled trichomes from a unicellular base, mixed with scattered simple uniseriate glandular trichomes with 4-celled heads, glabrescent in age, all trichomes less than 0.5 mm long.
Sympodial structure:
Sympodial units 2-foliate (rarely 3-foliate); internodes 2-6 cm long.
Leaves:
Leaves interrupted imparipinnate, 3.5-13 (-16) cm long, 1-6 (-8) cm wide, bright green, minutely pubescent with stiff simple uniseriate trichomes like those of the stems, pubescence more abundant abaxially, especially along the veins; primary leaflets 3-7 pairs, gradually becoming smaller towards the base of the leaf, subopposite to alternate, narrowly elliptic, the base truncate, more or less oblique basiscopically, the margins deeply and irregularly lobed to occasionally almost entire in some leaflets, the apex acute to acuminate; terminal leaflet 1.2-2.5 cm long, 0.4-1.5 cm wide, the petiolule 0.2-0.5 (-1) cm long, the apex acute to acuminate; lateral leaflets 0.7-2.5 cm long, 0.3-1.2 cm wide, the petiolule 0-0.5 (1) cm long, usually decurrent on the rachis basiscopically; secondary leaflets occasionally present in some leaflets, especially acroscopically, 0.3-0.5 cm long, 0.25-0.4 cm wide, sessile and decurrent on the leaflet rachis; tertiary leaflets absent; interjected leaflets (0-) 3-12 (-20), 0.2-0.5 cm long, 0.1-0.4 cm wide, sessile and decurrent on the main leaf rachis, often 2 sets of unpaired interjected leaflets between each set of primary lateral leaflets; petiole 1-4 (-6) cm long; pseudostipules present or absent, if present then present on most nodes, 0.3-0.4 cm long, 0.2-0.3 cm wide.
Inflorescences:
Inflorescences (6-) 12-30 cm long, once branched, usually regularly bifurcate, with 8-30 flowers, ebracteate or bracteate on most nodes from the base, the bracts 0.2-0.6 cm long, 0.1-0.4 cm wide, the largest bract at the bifurcation and first nodes, peduncle 5-15 cm long, minutely pubescent like the stems, with more prominent and numerous glandular trichomes especially at the apex. Pedicels 0.8-1.6 cm long, articulated in the distal half. Buds 1-1.2 cm long, 0.4-0.5 cm wide, narrowly conical, straight or curved at the very tip, with the corolla more than half exserted from the calyx just before anthesis.
Flowers:
Flowers with the calyx tube minute, ca. 0.05-0.1 cm long, the sinuses often hyaline, the calyx lobes 0.25-0.5 cm long, 0.1-0.15 cm wide, lanceolate or in some populations (Río Fortaleza) the tips rounded, minutely pubescent like the rest of the inflorescence with short, simple uniseriate 1-2-celled white trichomes; corolla 1.8-2.5 cm in diameter, stellate, yellow, the tube 0.2-0.5 cm long, the lobes 1-1.5 cm long, 0.3-0.7 cm wide, uniformly and sparsely pubescent abaxially with 1-celled uniseriate trichomes, these not more abundant along the midveins, the lobe tips elongate and acuminate, reflexed at anthesis; staminal column 1-1.2 cm long, straight or curved, the filaments less than 0.5 mm long, the anthers 0.4-0.6 cm long, the sterile apical appendage 0.15-0.4 cm long; ovary conical to globose, minutely and sparsely pubescent with simple trichomes at the apex; style 0.8-1.2 cm long, ca. 0.5 mm in diameter, sparsely pubescent in the basal half, exserted 0.5-1.7 mm from the staminal column; stigma capitate, green.
Fruits:
Fruit 1-1.4 cm in diameter, globose, 2-locular, green with a dark green or purple stripe from the apex to the base at fruit maturity, sparsely pubescent with weak-walled simple uniseriate trichomes to 0.5 mm long and occasionally also with minute glandular trichomes with 4-celled heads; fruiting pedicels 1-2 cm long, straight or slightly incurved towards the inflorescence axis; calyx lobes in fruit 1.1-1.6 cm long, 0.15-0.2 cm wide, spreading in some populations (Fortaleza) the lobe tips recurved.
Seeds:
Seeds 2.4-3 mm long, 1.1-1.5 mm wide, 0.5-0.6 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.
Distribution:
On the rocky slopes around Callejón de Huaylas along the Río Santa in the Department of Ancash, Peru and in the adjacent Río Fortaleza drainage; 1700-3000 m.
Phenology:
Solanum huaylasense flowers from March to May, and fruiting material has been collected from May to August.
Phylogeny:
Solanum huaylasense is a member of the Potato clade (sensu Weese & Bohs, 2007); within the tomatoes and wild relatives it is a member of the “Eriopersicon group” and is a member of section Lycopersicon.
References:
Solanum huaylasense is a member of a clade containing S. chilense, S. corneliomulleri, and S. peruvianum s.str. (+ in some analyses S. habrochaites). It is most similar to S. chilense, from which it differs in its less pubescent (green) leaves and slightly smaller flowers. The two species share the elongate peduncle and bifid inflorescence. Populations from Río Fortaleza (high up in the Callejón de Huaylas) are slightly more pubescent than the others, and have curved buds and recurved calyx lobe tips in fruit. Solanum huaylasense grows in rocky cliff faces near the type locality (B. León, pers. comm.) and is generally a straggling, lanky plant in the wild. Solanum huaylasense was previously considered part of the broadly defined S. peruvianum s.l. The table lists all the TGRC accessions (LA numbers) previously included in Rick’s broad definition of S. peruvianum with their current identification.
Solanum huaylasense is a priority for conservation due to its narrow range, the paucity of collections and lack of knowledge about population status.
Cultivated specimens of Solanum huaylasense are robust and erect plants during initial growth and later decumbent, with highly dissected leaves, very long peduncles, inflorescences typically two-branched but often three-branched. Stems, internodes, leaves, inflorescences, flowers, and fruits are usually larger in cultivation than in the wild, but maintain similar character proportions to those collected in the wild.