Solanum fragile Wedd., Chlor. And. 2: 105. 1859.

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

18. Solanum fragile Wedd., Chlor. And. 2: 105. 1859.

Figs 56 , 57

Solanum atriplicifolium Gillies ex Nees var. minus Gillies ex Nees, Nov. Act. Acad. Caes. Leop. 19, Suppl. 1: 387. 1843. Type. Peru. "Laguna de Titicaca, 12,400 ft.", "In planitie circa Tacoram [ Volcán Tacora], 14,000-17,000 ft., Apr" both syntypes collected by F.J.F. Meyen s.n. (no herbaria cited; possible original material: B, destroyed [F neg. 2598]). Peru. Puno: Prov. Puno, 19.5 km from Puno on rd to Tiquillaca, 3,982 m, 22 Mar 2012, T. Särkinen, A. Mathews & P. Gonzáles 4058 (neotype, designated here: USM [acc. # 00264006]; isoneotype: BM [BM001114837]).

Solanum hauthalii Bitter, Bot. Jahrb. Syst. 50, Beibl. 111: 61. 1913. Type. Bolivia. La Paz: "La Paz-Palca-Illimani, 3,600-4,800 m", R. Hauthal 269 (syntype: B, destroyed [F. neg. 2714]); "in valle inferoire Chuquiaguillo [Chuquiguillo] prope La Paz ad orientem, 3,500-4,000 m", R. Hauthal 165 (no herbarium cited). Bolivia. La Paz: Pacajes, hills above the town of Comanche, 4,100 m, 4 Feb 1995, E. Emschwiller EE-383 (neotype, designated here: LPB; isoneotypes: BH [000040588], F [v0472073F, acc. # 2286981; v0472074F, acc. # 2289672], NY [00852739]).

Type.

Peru. Tacna: "rochers humides de la Cordillere de Tacora ", 4,000 m, 1851, H. Weddell s.n. (lectotype, designated by Edmonds 1972, pg. 101 [as holotype]: P [P00335346]) .

Description.

Herb or shrublet from a woody base to 0.4 m high, the branches erect to spreading, brittle at the base, easily breaking from the woody rootstock. Stems slightly angled, densely pubescent with transparent to whitish cream mixed eglandular and glandular 2-3 celled simple uniseriate trichomes to 0.5 mm long, the gland if present single-celled; new growth densely pubescent with the same transparent to whitish cream mixed eglandular and glandular 2-3 celled simple uniseriate trichomes to 0.5 mm long; bark of older stems pale yellowish brown, glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple and shallowly toothed, the blades 1.2-7 cm long, 0.7-4.5 cm wide, ovate to rhomboid, widest in the lower half, membranous to somewhat fleshy and rubbery, discolorous; adaxial surfaces sparsely to moderately and evenly pubescent with stiff, patent, transparent glandular 2-3-celled simple uniseriate trichomes to 0.5 mm long, these to 1 mm long on the veins; abaxial surfaces similarly glandular-pubescent, the pubescence slightly denser, but not markedly so; principal veins 4-5 pairs, drying dark brown to blackish brown, more densely pubescent than the lamina especially abaxially; base truncate and abruptly attenuate onto the petiole; margins shallowly toothed, the teeth 1-2 mm long, 2-4 mm wide, with rounded tips, the sinuses reaching less than 1/8 of the way to the midrib; apex acute to rounded; petioles 0.2-0.4 cm long, the winged portion from the decurrent leaf base very narrow, densely pubescent with transparent to whitish cream mixed eglandular and glandular 2-3 celled simple uniseriate trichomes to 0.5 mm long. Inflorescences internodal, forked or less commonly several times branched, (1.5)3-5 cm long, with (3)9-12 flowers clustered in the distal parts of the branches, densely pubescent with transparent to whitish cream mixed eglandular and glandular 2-3 celled simple uniseriate trichomes to 0.5 mm long like the stems; peduncle 1-2 cm long; pedicels 0.7-1 cm long, ca. 0.75 mm in diameter at the base and apex, not markedly tapering, spreading at anthesis, densely pubescent with transparent to whitish cream mixed eglandular and glandular 2-3 celled simple uniseriate trichomes to 0.5 mm long, articulated at the base; pedicel scars irregularly spaced 0.5-1(5) mm apart. Buds globose, the corolla halfway exserted from the calyx before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 1-2 mm long, strongly cup-shaped and abruptly narrowing to the pedicel apex, the lobes 2-3 mm long, ca. 1 mm wide, triangular with blunt tips, densely pubescent with transparent to whitish cream mixed eglandular and glandular 2-3 celled simple uniseriate trichomes to 0.5 mm long and glandular papillae. Corolla 1.5-1.6 cm in diameter, white or violet, with a green eye extending along the lobe midveins, stellate, lobed ca. halfway to the base, the lobes 5-6 mm long, 3-4 mm wide, broadly deltate, spreading at anthesis, adaxially glabrous, abaxially densely puberulent with white eglandular simple uniseriate trichomes to 0.4 mm long, densely papillate on tips and margins. Stamens equal; filament tube minute; free portion of the filaments ca. 0.5 mm, sparsely pubescent with tangled transparent simple uniseriate trichomes adaxially; anthers 2.5-3 mm long, ca. 1.5 mm wide, plumply ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary glabrous, conical; style ca. 9 mm long (Knapp et al. 10259 with styles 4 mm long), strongly curved in bud, straight, long-exserted from the anther cone, glabrous; stigma large, globose and capitate, the surface minutely papillate, bright green in live plants. Fruit a globose berry, 0.5-0.8 cm in diameter, green when ripe, the pericarp glabrous, thin or somewhat stiff and leathery, shiny, opaque, glabrous; fruiting pedicels 0.8-1.2 cm long, ca. 0.75 mm in diameter at the base, ca. 1 mm in diameter at the apex, not markedly woody, deflexed, not persistent or occasionally remaining on the inflorescence axis; fruiting calyx somewhat enlarged, the tube to 2 mm long, the lobes to 3 mm long, spreading and the tips slightly reflexed. Seeds ca. 30 per berry, ca. 2 mm long, ca. 1.5 mm wide, flattened to slightly ovoid reniform, straw-coloured or yellowish brown, the surfaces minutely pitted, the testal cells sinuate in outline. Stone cells absent. Chromosome number: reported as 2n = 48 ( Edmonds 1972, 1977, vouchers Iltis et al. 481b, Hawkes et al. 4110, Gade s.n.; none found for verification).

Distribution

(Fig. 58 ). Solanum fragile is an Andean species, occurring from Peru (Depts. Ancash, Arequipa, Ayacucho, Cusco, Huancavelica, Lima, Moquegua, Puno, Tacna) to Bolivia (Depts. La Paz, Oruro, Potosí) and northern Chile ( Regíon I [ Tarapacá]).

Ecology and habitat.

Solanum fragile grows in grassy puna vegetation among rocks and at the bases of cliffs, from 2,165 to 4,500 m elevation.

Common names and uses.

Peru. Ancash: japchilla (Cerrate & Ferreyra 7015). No uses recorded.

Preliminary conservation status

( IUCN 2022). Least Concern [LC]. EOO = 338,395 km2 [LC]; AOO = 176 km2 [EN]. Solanum fragile is not common where it occurs but has a relatively wide distribution and does not appear to be habitat specific. It is found in the region of the Lake Titicaca Reserve in Peru and Bolivia but has not been specifically recorded within a protected area.

Discussion.

Solanum fragile is morphologically similar to the sympatric S. grandidentatum . Both are glandular-pubescent plants with incised, shallowly lobed leaves and green berries. Solanum fragile differs from S. grandidentatum in its possession of a woody rootstock with brittle stems (herbarium specimens are often only of the single stems that break off); S. grandidentatum is a shrubby plant with conspicuous aboveground branching. In live plants in the field, leaves of S. fragile , although glandular-pubescent, are odourless, but those of S. grandidentatum have a strong odour; leaf bases of S. fragile are truncate, while those of S. grandidentatum are more attenuate. Although the stamens of these two species are similar, the ratio of anthers to filaments is markedly different; S. fragile has anthers 2.5-3 mm long and filaments ca. 0.5 mm long, while S. grandidentatum has anthers 2-2.5 mm long and filaments 1-1.2 mm long.

Molecular sequence data suggest the two species are not closely related ( Särkinen et al. 2015b; Gagnon et al. 2022), but this result could be affected by polyploidy. Solanum grandidentatum has a vouchered chromosome count of 2n = 48 (tetraploid) and S. fragile is also recorded as being tetraploid (2n = 48, see above) but we have been unable to find the vouchers for this information; it needs reconfirmation. Both species are part of weakly supported groups (polytomies), but different ones (see appendix S11 in Gagnon et al. 2022).

In describing S. atriplicifolium var. minus , Nees von Esenbeck (1843) expressed some doubt as to its identity ("Var. β alieni quid prae se fert, et dubito, an huiis specie, an potius Solani furcati, nanam [nanum] prolem esse dicam" - [Var. β is strange and may be dwarf or perhaps Solanum furcatum ]). No herbaria were cited in the protologue, but Franz Meyen’s herbarium from his South American travels was held in B and destroyed. A sheet in B photographed by J.F. Macbride (F. neg. 2598) is annotated by Bitter with an observation that it was the sheet referred to by Dunal (1852) as S. atriplicifolium var. minus but clearly was not that species ("Dies ist die Pflanze vom Originalfundort des S. atriplicifolium Gill. Var. β minus bei Dunal in DC. N. 78 haupt offtenbar nicht mit S. atriplicifolium zusammen" - [This is the plant that is the original of S. atriplicifolium Gill. var. β minus in Dunal in DC. n. 78 and is obviously not associated with S. atriplicifolium ]). To date we have found no duplicates of either Meyen collection cited in the protologue, but have not comprehensively searched all the herbaria where duplicates might be found. We select here a recent collection for southern Peru in the Lake Titicaca area ( Särkinen et al. 2058, USM acc. # 00264006) as a neotype.

Bitter (1913) cited two collections (Hauthal 165, 269) in the protologue of S. hauthalii , citing "herb. Berol." as the location only for Hauthal 269 and no herbarium for Hauthal 165. The specimen of Hauthal 269 was photographed in Berlin (F neg. 2714) and corresponds to S. fragile ; we have found no duplicates of either of these collections where Rodolfo Hauthal’s specimens are known to be deposited (e.g., GOET, NY fide Funk and Mori 1989). Although we have seen no recent collections from the trajectory between La Paz and Nevado Illimani we have selected a recent collection from a similar elevation with many duplicates as the neotype for this name (Emschwiller EE-383, neotype at LPB).

Figures

Figure 56. Solanum fragile A habit B inflorescence with flowers C inflorescence with fruits (A, B Knapp et al. 10233 [BM 001114738] C Beck 11788 [K 000658368]). Reproduced with permission of the Trustees of the Natural History Museum and Royal Botanic Gardens, Kew.

Figure 57. Solanum fragile A habit B inflorescence with buds C flowers at full anthesis D maturing fruits (A-D Knapp et al. 10259). Photos by S. Knapp.

Figure 58. Distribution map of Solanum fragile.