Solanum subtusviolaceum Bitter, Repert. Spec. Nov. Regni Veg. 11: 207. 1912.

Knapp, Sandra, Saerkinen, Tiina & Barboza, Gloria E., 2023, A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae), PhytoKeys 231, pp. 1-342 : 1

55. Solanum subtusviolaceum Bitter, Repert. Spec. Nov. Regni Veg. 11: 207. 1912.

Figs 166 , 167

Type.

Bolivia. “Yungas”, 22 Aug 1894, M. Bang 2392 (lectotype, designated here: NY [00172194]; isolectotypes BM [BM000617681], E [E00190737], F [v0073422F, acc. # 163942], G [2 sheets], GH [00077769], K [K000585515], M [M0166060], MO [MO-503622, acc. # 1815481], NY [00172192, 00172193], PH [00030484], US [00650473, acc. # 32986; 00027817, acc. # 1324786], W [acc.# 1895-001067], WIS [v0256269WIS]).

Description.

Sprawling herbs to small shrubs to 0.45 m high, the branches erect or somewhat lax. Stems terete, densely pubescent with spreading transparent glandular simple uniseriate ca. 10-celled trichomes 3(4) mm long, the gland single-celled and globose or with more than one cell and slightly elongate; new growth densely pubescent with transparent glandular simple uniseriate trichomes to 4 mm long like those of the stems, these spreading; bark of older stems somewhat glabrescent, brownish red or pale tan. Sympodial units unifoliate or difoliate, the leaves not geminate. Leaves simple and variously irregularly toothed, the blades 2.5-13 cm long, 1.5-9 cm wide, larger on lower branches, ovate or slightly rhomboidal, widest in the lower third, membranous, discolorous; adaxial surfaces moderately and evenly pubescent on veins and lamina with transparent glandular 6-10-celled simple uniseriate trichomes to 3 mm long, these spreading and somewhat weak and collapsing in dry specimens, the glands usually single-celled; abaxial surfaces similarly pubescent with transparent glandular trichomes on veins and lamina, often purplish in both live plants and dried specimens; principal veins 6-8 pairs, drying yellowish or pale green; base truncate then abruptly attenuate and somewhat decurrent onto the petiole; margins irregularly toothed, the teeth to 10 mm long, ca. 7 mm wide, with acute apices, the sinuses rounded, reaching to 1/4 of the way to the midrib; apex acuminate; petioles 1-3.5 cm long, glandular-pubescent like the stems and leaves. Inflorescences opposite the leaves or borne just below the leaf node, unbranched (occasionally forked), 2-3 cm long, with 4-6 flowers in the distal third of the axis, densely pubescent with spreading, transparent glandular 6-10-celled simple uniseriate trichomes to 3 mm long, the glands usually single-celled; peduncle 1.5-2 cm long; pedicels (0.5)0.7-1 cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, tapering, spreading to deflexed at anthesis, densely pubescent with spreading, transparent glandular 6-10-celled simple uniseriate trichomes like the rest of the inflorescence, articulated at the base; pedicel scars 0.5-2 mm apart, more closely spaced distally. Buds ellipsoid to globose-ellipsoid, the corolla barely exceeding the calyx lobes before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 1.5-2 mm long, conical, the lobes (2)2.5-3.5 mm long, ca. 1 mm wide, long-triangular (lobes on type triangular), distinctly different in texture to the tube, densely pubescent with spreading, transparent glandular 6-10-celled simple uniseriate trichomes to 3 mm long, the glands usually single-celled. Corolla (1.5)1.8-2 cm in diameter, white or white tinged or striped with violet, with a darker yellow-green or purple eye (the eye drying dark), stellate, lobed ca. 2/3 of the way to the base, the lobes 4-7 mm long, 2-3 mm wide, triangular, spreading to strongly reflexed at anthesis, adaxially glabrous, abaxially densely papillate at the tips and margins, sparsely pubescent with transparent eglandular simple uniseriate trichomes to 2.5 mm long at lobe tips and along petal midveins. Stamens equal; filament tube minute; free portion of the filaments 1-1.5 mm long, glabrous or with a few tangled transparent eglandular simple uniseriate trichomes adaxially; anthers 3-4 mm long, 1-1.2 mm wide, ellipsoid, yellow, poricidal at the tips the pores lengthening to slits with age. Ovary conical, glabrous; style 5-6(7) mm long, straight, exserted beyond the anther cone, densely papillate and pubescent with eglandular transparent tangled simple uniseriate trichomes to 0.5 mm in the lower 2/3; stigma small capitate, the surface minutely papillate. Fruit a globose berry, 0.7-0.8 cm in diameter, green (immature?), drying pale whitish grey, the pericarp thin, matte, opaque, glabrous; fruiting pedicels 1-1.2 cm long, ca. 0.75 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, not markedly woody, deflexed or spreading, not persistent; fruiting calyx slightly accrescent, the tube ca. 2 mm long, the lobes to 5 mm long, appressed or the tips spreading. Seeds ca. 20 per berry, ca. 1.5 mm long, ca. 1 mm wide, flattened and teardrop shaped, tan, the surfaces minutely pitted, the testal cells pentagonal in outline or the walls somewhat sinuate. Stone cells 4, scattered through the mesocarp or sometimes 2 more apically (fide Bitter 1912c), ca. 0.5 mm in diameter, cream-coloured. Chromosome number not known.

Distribution

(Fig. 168 ). Solanum subtusviolaceum occurs along the eastern slopes of the Andes in Peru (Depts. Cusco, Junín, Pasco) and northern Bolivia (Depts. Cochabamba, La Paz).

Ecology and habitat.

Solanum subtusviolaceum grows in premontane, montane and cloud forests, at forest gap edges and along roadsides, from 750 to 4,100 m elevation.

Common names and uses.

None recorded.

Preliminary conservation status

( IUCN 2022). Least Concern [LC]. EOO = 163,921 km2 [LC]; AOO = 100 km2 [EN]. Solanum subtusviolaceum has a broad geographical distribution and is a plant of forest edges and borders. It has been collected in protected areas in Bolivia (Parque Nacional Carrasco) and Peru (Parque Nacional Yanachaga-Chemillén).

Discussion.

Solanum subtusviolaceum is one of the glandular-pubescent species from the Andes without accrescent calyces (although Nee 55287 from Dept. Cochabamba in Bolivia is an aberrant glabrous individual). It is morphologically most similar to S. juninense , with which it shares shallowly toothed leaves, long (to 2 mm long) glandular trichomes and corollas with a dark central eye. Solanum subtusviolaceum has longer, more narrowly triangular (2.5-3.5 mm long versus 1.5-2 mm long) calyx lobes and more stone cells per berry (4 versus 1-2) than S. juninense , and the inflorescences are usually unbranched (rather than consistently forked) although some specimens of S. subtusviolaceum have some forked inflorescences. Solanum juninense has a more northerly distribution in Peru than S. subtusviolaceum , which occurs from central Peru to northern Bolivia. Leaves of S. subtusviolaceum are often tinged with purple beneath and usually more truncate at the base than those of S. juninense . In S. subtusviolaceum , the corolla eye is markedly dark in dry material, although this can also be the case in some specimens of S. juninense . Solanum subtusviolaceum differs from the lower elevation glandular-pubescent S. arenicola in its larger flowers (1.5-2 cm in diameter versus 0.8-1.2 cm in diameter), its more deeply divided calyx and the slightly larger (0.7-0.8 cm in diameter versus 0.3-0.7 cm in diameter) with fewer (ca. 20 versus 35-45) seeds.

Bitter (1912b) cited Bang 2392 from "herb. Berol.!, Vratisl.!" in the protologue of S. subtusviolaceum , also stating that the specimens had been determined as " S. atriplicifolium Gill." We have not found either of these two duplicates of this widely distributed Miguel Bang gathering and so designate the best preserved of the three duplicates of Bang 2392 at NY (barcode 00172194) as the lectotype for S. subtusviolaceum ; this sheet bears Bang’s original field label and has both flowers and immature fruits.

Figures

Figure 166. Solanum subtusviolaceum A flowering branch B inflorescence C flower at anthesis D flower opened E calyx F glandular trichome G stamen adaxial view H stamen abaxial view I style J eglandular trichome (A-J Krukoff 10378). Illustration by L. Ribulgo.

Figure 167. Solanum subtusviolaceum A habit B flowering branch with flowers at full anthesis C maturing fruits (A-C Orejuela 2833). Photos by A. Orejuela.

Figure 168. Distribution map of Solanum subtusviolaceum.