Solanum gilioides Rusby, Mem. Torrey Bot. Club 4: 228. 1895.

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

20. Solanum gilioides Rusby, Mem. Torrey Bot. Club 4: 228. 1895.

Figs 62 , 63

Solanum nicandricalyx Cabrera, Bol. Soc. Argent. Bot. 13(4): 326. 1971. Type. Argentina. Jujuy: Dpto. Tilcara: Falda Grande, Cerro de Guairahuasi, A. Cabrera & P. Hernández 14026 (holotype: LP; isotype: CORD [CORD00012842, fragment of LP holotype]).

Type.

Bolivia. Cochabamba: "vic. Cochabamba ", 1891, M. Bang 938 (no herbaria cited; lectotype, designated here: NY [00172004, R-hand plant stems only]; isotypes: BM [BM000778106], E [E00190739], G [G00370047], GH [00077670], K [K000585518], NDG [ NDG45048 ], NY [00172003], PH [00030413], US [00027580, acc. # 1324554; 00650469, acc. # 3412819]).

Description.

Small annual herbs (0.05) 0.1-0.5 m high, usually prostrate and spreading. Stems terete, sparsely pubescent with transparent 4-6-celled simple uniseriate trichomes 0.5-1 mm long, these mixed glandular and eglandular; new growth densely to moderately pubescent with a mixture of glandular 1-celled papillae and transparent 4-6-celled simple uniseriate trichomes 0.5-1.5 mm long; older stems pale greenish yellow, glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, shallowly to deeply lobed, extremely variable even on a single plant, the blades 1.5-6.5 cm long, 0.6-2.4 cm long, narrowly elliptic in outline, widest at the middle, membranous to slightly thick and fleshy, concolorous; adaxial surfaces glabrous; abaxial surfaces sparsely pubescent with mixed glandular and eglandular 4-6-celled simple uniseriate trichomes 0.5-1 mm long on the veins and margins; principal veins 3-4(5) pairs, each ending in a lobe; base attenuate onto the petiole; margins shallowly to deeply lobed, the sinuses reaching ca. halfway to the midrib or less, the lobes 0.3-1 cm long, irregular, triangular to deltate with acute tips; apex acute and somewhat rounded; petiole 0.5-1.4 cm long, sparsely pubescent with eglandular white uniseriate trichomes ca. 0.5 mm long. Inflorescences opposite the leaves, unbranched, 1.2-4.5 cm long, with 2-7 flowers clustered at the tip, moderately pubescent with mixed glandular and eglandular simple uniseriate trichomes 0.5-1 mm long, always denser and longer than the stem pubescence; peduncle 1.2-5 cm long; pedicels (0.5)1-1.3 cm long, ca. 0.5 mm in diameter at the base, ca. 0.5 mm in diameter at the apex, drying purple in herbarium specimens, filiform, spreading at anthesis, moderately pubescent with a mixture of glandular papillae and eglandular simple uniseriate trichomes ca. 0.5 mm long, similar in density to the inflorescence, articulated at the base; pedicel scars tightly packed and spaced 3-5 mm apart in both flower and fruit. Buds globose, the corolla only just exserted from the calyx before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube ca. 2 mm long, conical, the lobes 2-2.5 mm long, 1.5-2 mm wide, narrowly deltate, sparsely to moderately pubescent with glandular papillae and eglandular simple uniseriate trichomes to 0.5 mm like those of the rest of the inflorescence, the venation prominent and drying dark purple or black. Corolla ca. 1.6 cm in diameter, violet to purple with a green central eye, rotate, lobed less than 1/4 of the way to the base, the lobes (acumens) 1-2 mm long, 3-4 mm wide, spreading or slightly cupped at anthesis, adaxially glabrous, abaxially glabrous but densely papillose on the acumen tips. Stamens equal; filament tube ca. 0.5 mm long; free portion of the filaments ca. 1.5 mm long, sparsely pubescent adaxially with tangled transparent simple uniseriate trichomes; anthers 1-3 mm long, 0.6-1 mm wide, yellow, ellipsoid with a somewhat prolonged and pointed tip, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style (1)3-6 mm long (plants possibly heterostylous?), straight, exserted beyond the anther cone, glabrous; stigma capitate, the surface minutely papillose. Fruit a globose to somewhat ellipsoid berry, 0.6-0.7 cm long, 0.4-0.6 cm in diameter, green when mature(?), the pericarp thin, matte, opaque, glabrous; fruiting pedicels ca. 1.2 cm long, ca. 0.5 mm in diameter at the base, ca. 0.5 mm in diameter at the apex, not markedly woody, erect or spreading, not persistent; fruiting calyx accrescent and inflated, completely covering the berry, the tube ca. 5 mm long, strongly angled, the lobes ca. 10 mm long, ca. 6 mm wide, sharply pointed, somewhat overlapping and creating strong angles in the suture, the venation very evident, often drying blue or purple, the base invaginate. Seeds 9-20 per berry, 1.7-2.2 mm long, 1.4-1.7 mm wide, reniform, dark brown, the surfaces tuberculate, the testal cells pentagonal to rectangular in outline. Stone cells absent. Chromosome number: not known.

Distribution

(Fig. 64 ). Solanum gilioides is found from Bolivia (Depts. Cochabamba, Potosí, Tarija) to northern Argentina (Provs. Jujuy, Salta, Tucumán).

Ecology and habitat.

Solanum gilioides grows in rocky, grassy puna habitats, from 2,500 to 4,200 m, usually growing above 3,000 m elevation.

Common names and uses.

None recorded.

Preliminary conservation status.

Least Concern [LC]. EOO = 139,358 km2 [LC]; AOO = 64 km2 [EN]. Although relatively rarely collected, S. gilioides occurs over a wide geographic range and in places rarely visited by botanists. The high elevation habitats where it occurs, however, are often the sites of mines, and S. gilioides has not been recorded within any protected area. It may in future warrant an assessment of Near Threatened.

Discussion.

Solanum gilioides is a species of high elevations and was segregated, along with S. annuum and S. weddellii (as S. chamaesarachidium ) as section Solanum Chamaesarachidium Bitter ( Barboza 2003). Phylogenetic analysis with molecular sequence data confirms the close relationship of S. gilioides and S. weddelli , but not S. annuum ( Särkinen et al. 2015b), whose relationships appear to be with other Black nightshades. Solanum gilioides is broadly sympatric with S. weddellii , also of high elevations, but that species tends to occur in sandy, rather than rocky habitats. The taxa both have strongly inflated calyces in fruit, but those of S. gilioides are larger and the lobes have acute to acuminate tips. The calyx lobes of S. gilioides are fused, like those of most species of Physalis while in S. weddellii the lobes remain free but overlapping. In both dried and fresh material of S. gilioides the stiff calyx lobes often have striking purple veins (Fig. 63A ). Pubescence in S. gilioides is eglandular except for tiny glandular papillae, while S. weddellii often has longer, several celled glandular trichomes on leaves and stems. The flowers of S. gilioides are larger than those of S. weddellii (ca. 1.6 cm versus 0.6 cm in diameter, with anthers 1-3 mm long versus ca. 1 mm long).

The lectotype we have selected for S. gilioides (NY, barcode 00172004) is the sheet incorrectly referred to as “holotype” by Barboza et al. (2013). Only the right-hand stems on this sheet are referrable to S. gilioides , the single stem on the left is a small plant of S. sisymbriifolium Lam., a member of the Leptostemonum clade. The two taxa are not easily confused, as S. sisymbriifolium has copious prickles and stellate pubescence.

Figures

Figure 62. Solanum gilioides A habit B flowering plant showing different leaf shapes and annual habit C detail of adaxial leaf surface D detail of abaxial leaf surface E trichomes on leaves F flower bud G dissected flower H maturing fruit with inflated calyx I seed (A, C, D, H Wood et al. 21974 B, F, G Wood et al. 19056 E, I Negritto et al. 429). Illustration by R. Wise and L. Ribulgo.

Figure 63. Solanum gilioides A habit B smaller habit with variable leaf shape (A Wood et al. 19209 [K 000441056] B Bang 938 [E 00190739]). Reproduced with permission of the Trustees of the Royal Botanic Gardens, Kew and Royal Botanic Garden Edinburgh.

Figure 64. Distribution map of Solanum gilioides.