61. Solanum woodii Särkinen & S.Knapp, PhytoKeys 74: 26. 2016.

Figs 184, 185

Type.

Bolivia. Santa Cruz: Prov. Valle Grande, pasando el puente Santa Rosa, a 78 km desde Serrano hacia Valle Grande, 1,169 m, 4 Apr 2003, J.R.I. Wood 19616 (holotype: LPB).

Description.

Decumbent, slender annual (fide labels) herbs to 0.3-0.4 m high, much branching. Stems terete, pale yellow or greenish beige, glabrescent; new growth densely pubescent with spreading translucent 5-8-celled simple uniseriate glandular trichomes ca. 0.5 mm long, some to 1 mm. Sympodial units difoliate, not geminate. Leaves simple and often shallowly toothed, the blades (2.3-)4.5-8 cm long, (1.5-)2.2-4.3 cm wide, elliptic to ovate, widest at the middle or in the lower third, thin-membranous, slightly discolorous; adaxial surface moderately pubescent with spreading hairs as on stem evenly spaced along lamina and veins; abaxial surface more densely pubescent along veins; major veins 5-7 pairs; base attenuate to decurrent; margins entire to shallowly and unevenly toothed, the lobes narrow; apex acute; petiole 0.8-4.5 cm long, sparsely pubescent with simple 5-8-celled uniseriate trichomes like those of the stems. Inflorescences unbranched, opposite the leaves, 1.5-3 cm long, with (2-)3-7 flowers, sparsely pubescent with simple 5-8-celled uniseriate trichomes like those of the stems; peduncle 0.9-1.8 cm long, ca. 0.3 mm in diameter at the apex and ca. 0.5 mm in diameter at the base; pedicels spaced 0-1 mm apart, 0.7-1.1 cm long, ca. 0.2 mm in diameter at the base and ca. 0.3 mm in diameter at the apex, straight and spreading at anthesis, articulated at the base. Buds ovoid, white, the corolla strongly exserted from the calyx before anthesis, exceeding the lobes by up to two times their length. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 0.6-0.7 mm long, the lobes 1.2-2.1 mm long, 0.8-1 mm wide, ovate to elliptic in outline with acute apices, somewhat spreading at anthesis, sparsely pubescent with simple 5-8-celled uniseriate glandular trichomes like those of the stems. Corolla 1-1.5 cm in diameter, white with a greenish-purple central star at the base, stellate, lobed to the middle, the lobes 4-6 mm long, 2-3 mm wide, reflexed at anthesis, sparsely pubescent abaxially with very short 1-2-celled simple uniseriate eglandular trichomes. Stamens equal; filament tube ca. 0.5 mm long; free portion of the filaments 0.1-0.4 mm long, adaxially pubescent with 4-7-celled uniseriate eglandular trichomes; anthers (2.5-)3-3.8 mm long, 1.2-1.4 mm wide at base, ca. 0.5 mm at tip, tapering and narrowly triangular to triangular in outline, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary globose, glabrous; style 4.5-5 mm long, curved at the very tip, exserted beyond the anther cone, densely pubescent with 2-3-celled simple uniseriate trichomes in the basal 1/3 where included in the anther cone; stigma minutely capitate, the surface papillate. Fruit a globose berry, 0.5-0.9 cm in diameter, green (immature), the pericarp thick and shiny, opaque, glabrous; fruiting pedicels 0.7-1 cm long, ca. 0.5 mm in diameter at the base, ca. 0.6 mm in diameter at the apex, spaced 0-1 mm apart, spreading to recurved, not persistent; fruiting calyx tube ca. 1 mm long, the lobes 2-3.5 mm long, spreading to reflexed. Seeds 15-30 per berry, 1.6-2 mm long, 1-1.5 mm wide, flattened, teardrop-shaped with a subapical hilum, yellow, the surface minutely pitted, the testal cells pentagonal in outline with the lateral cell walls elongate and the seeds from mature fruits appearing hairy. Stone cells absent. Chromosome number: not known.

Distribution

(Fig. 186). Solanum woodii occurs in Bolivia (Depts. Chuquisaca, Santa Cruz) and in northern Argentina (Prov. Jujuy). When originally described (Särkinen and Knapp 2016), it was thought to be a Bolivian endemic.

Ecology and habitat.

Solanum woodii grows in Chaco and Chaco forests of inter-Andean valleys in Bolivia and northern Argentina, in dry Chaco woodlands on sandy and clay soils near water sources, rivers and in moist depressions in partial or full shade; between 300 and 1,800 m elevation.

Common names and uses.

None recorded.

Preliminary conservation status

(IUCN 2022). Least Concern [LC]. EOO = 122,138 km2 [LC]; AOO = 64 km2 [EN]. The preliminary threat status of S. woodii was assessed as Vulnerable (VU, B1) by Särkinen and Knapp (2016); recent collections from Argentina have revealed it to be more widely distributed than previously thought but is rare where it occurs. No occurrences are known within protected areas thus far.

Discussion.

Solanum woodii is unusual in South American morelloids having tapering, somewhat cone-shaped anthers with a beak-like tip (see Fig. 185C); this character, however, can be difficult to see in older flowers with dehisced anthers. Among other glandular-viscid herbaceous solanums, it could be confused with S. tweedieanum and S. physalifolium. Solanum woodii is sympatric with S. tweedieanum but the latter species has longer calyx lobes in flower (3.5-5(-7) mm) and fruit (>5 mm) and slightly larger ellipsoid anthers (3-)4-4.5 mm long that are rectangular in outline (equally wide along their entire length) rather than broadest at the base; the calyx of S. tweedieanum is accrescent and completely covers the berry at maturity, while that of S. woodii is spreading and does not become accrescent.

The unusual anther shape in S. woodii resembles that of S. anomalostemon from the dry inter-Andean valley of the Rio Apurimac in southern Peru (Knapp and Nee 2009). Despite the similarity in anther shape, preliminary molecular data suggest S. woodii is a member of the morelloid lineage, whereas S. anomalostemon is morphologically unique within Solanum in having cordate anthers and has been resolved as an independent lineage not closely related to the Morelloid clade (Gagnon et al. 2022).