Citation:
Izv. Akad. Nauk SSSR, Ser. Biol. 2: 313. 1937.
Type:
Peru. Pasco: Junín, between Cajamarca and Huariaca, 8 Mar 1927, S. Juzepczuk 10672 (lectotype, LE, designated by Ochoa, 1999 [Lechnovich unnumbered neg., LL]).
Habit:
Herbs 0.15-0.75 m tall, erect. Stems 2-6 mm in diameter at base of plant, unwinged, glabrous, woody.
Sympodial structure:
Sympodial units tri- to plurifoliate, not geminate.
Leaves:
Leaves odd-pinnate, the blades 6.5-13.5 x 3.3-11 cm, light green abaxially and dark green adaxially, coriaceous, glabrous adaxially, glabrous to glabrescent with very short hairs abaxially; lateral leaflet pairs 2-4, decreasing in size toward the leaf base, with the terminal leaflet generally subequal to the laterals; most distal lateral leaflets 2-10.5 x 0.6-3.5 cm, ovate to elliptic, the apex acute to acuminate, the base typically sessile and attenuate to rounded, asymmetric with more tissue on the basiscopic side, slightly decurrent on the rachis; terminal leaflet 4-7.5 x 2-2.6 cm, ovate to elliptic, the apex acute to acuminate, the base attenuate; interjected leaflets 0-14, sessile to short petiolulate, ovate to orbicular; petioles 1-1.7 cm, glabrous. Pseudostipules 3-6 mm long, glabrous to subglabrous.
Inflorescences:
Inflorescences 5.5-11.5 cm, terminal with a subtending axillary bud, generally in distal half of the plant, usually forked, with 10-26 flowers, with all flowers apparently perfect, the axes glabrous; peduncle 1.7-8.6 cm long; pedicels 25-35 mm long in flower and fruit, spaced 3-5 mm apart, articulated high in the distal half.
Flowers:
Flowers homostylous, 5-merous. Calyx 3-10 mm long, the tube 1-3 mm, the lobes ca. 8-9 mm, ovate to lanceolate, with linear acumens 3-4 mm long, glabrous. Corolla 3-4 cm in diameter, pentagonal to rotate, lilac to blue, the tube 1-2 mm long, the acumens 0.8-2 mm long, the corolla edges flat, not folded dorsally, glabrous abaxially and adaxially. Stamens with the filaments 1-2 mm long; anthers 3-6 mm long, lanceolate, connivent, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous; style 3-10 mm x ca. 1 mm, exceeding stamens by 3-4 mm, straight, glabrous; stigma clavate to capitate.
Fruits:
Fruit a globose berry, 1.5-1.8 cm in diameter, medium to deep green with purple stripes when ripe, glabrous.
Seeds:
Seeds from living specimens ovoid and ca. 2 mm long, whitish to greenish in fresh condition and drying brownish, with a thick covering of “hair-like” lateral walls of the testal cells that make the seeds mucilaginous when wet, green-white throughout; testal cells honeycomb-shaped when lateral walls removed by enzyme digestion.
Phenology:
Flowering and fruiting from January to May.
Solanum acroglossum is morphologically similar to S. piurae and some morphotypes of S. chomatophilum. Solanum piurae and S. chomatophilum both have blue corollas as does S. acroglossum, but S. acroglossum differs from S. piurae in its sessile leaflets; S. piurae has petiolulate leaflets. Solanum chomatophilum differs from S. acroglossum in the number of interjected leaflets; Solanum chomatophilum usually has around 20, whereas S. acroglossum generally has 0 to 14.