Solanum hunzikeri Chiarini & Cantero, PhytoKeys 164: 40. 2020.

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

25. Solanum hunzikeri Chiarini & Cantero, PhytoKeys 164: 40. 2020.

Figs 77 , 78

Type.

Argentina. Catamarca: Dpto. Ambato, Los Morteritos, Sierra de Ambato, falda E, subiendo desde El Rodeo hacia el Cerro Manchado [Cerro Manchao], 2,300-2,400 m, 13 Jan 1973, A.T. Hunziker & R. Subils 22205 (holotype: CORD [CORD00013086]) .

Description.

Herb or subshrub from a woody base ca. 0.5 m high. Stems terete or only slightly angled, densely glandular pubescent with glandular papillae and transparent spreading simple 3-8-celled uniseriate trichomes 0.5-1 mm long, some to 1.5 mm long; bark of older stems pale brown, glabrescent; new growth densely glandular pubescent with simple uniseriate trichomes to 1 mm long. Sympodial units plurifoliate, the leaves not geminate. Leaves simple, entire to shallowly toothed, the blades (2-)4.5-14 cm long, (1.1-)2-7 cm wide, elliptic in outline, widest at the middle, membranous or somewhat thick and fleshy, concolorous; adaxial surface moderately and evenly glandular pubescent with transparent spreading, simple uniseriate trichomes ca. 0.5 mm long on the lamina, ca. 1 mm long on the veins; abaxial surface moderately and evenly glandular pubescent like the adaxial surface, but the trichomes denser and longer, to 1.5 mm long; principal veins 4-7 pairs, densely glandular pubescent; base attenuate and strongly decurrent onto the petiole; margins entire or shallowly toothed, the teeth, if present, 1-2 mm long, 2-3 mm wide, broadly deltate with somewhat rounded tips; apex acute; petioles absent and the leaves sessile or 0-0.1 mm long, the decurrent leaf bases running onto the stem, glandular pubescent like the stems and leaves. Inflorescences opposite the leaves, unbranched but occasionally forked ( Rodríguez 1421), 2.5-4 cm long, with 10-20 flowers, densely glandular pubescent with transparent spreading simple uniseriate trichomes to 1.5 mm long; peduncle 1.2-2.5 cm long; pedicels 1.3-1.5 cm long, 0.5-0.7 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, spreading at anthesis, densely glandular pubescent, articulated at the base; pedicel scars irregularly spaced 1-2 mm apart. Buds ellipsoid, the corolla ca. halfway exserted from the calyx before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 2-3 mm long, conical, the lobes 2.5-4 mm long, long-triangular, densely glandular pubescent with simple uniseriate trichomes like the pedicels and rest of the inflorescence, the tips acuminate and somewhat recurved at anthesis. Corolla 1.6-2.5 cm in diameter, pale lilac to violet with a yellow-green central star, stellate, lobed ca. 1/2 way to the base, the lobes 5-5.5 mm long, 4-5.5 mm wide, deltate, reflexed or spreading at anthesis, adaxially glabrous, abaxially sparsely glandular papillate especially on the midvein, tips and margins; stamens equal; filament tube 0.35-0.5 mm; free portion of the filaments 1-1.5 mm, almost glabrous, but with a few tangled transparent eglandular simple uniseriate trichomes adaxially; anthers 4-5.5 mm long, 1.25-1.6 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style 7-8 mm long, straight, exserted beyond the anther cone, densely papillate with a few longer simple trichomes in the lower third; stigma large capitate to slightly bilobed, the surface minutely papillate. Fruit a globose berry, 1-1.2 cm in diameter, green (?) at maturity, the pericarp glabrous, thin, matte, opaque, glabrous; fruiting pedicels 1.5-2 cm long, ca. 1.5 mm in diameter at the base, ca. 2 mm in diameter at the apex, somewhat woody, deflexed from the weight of the berry, glandular pubescent to somewhat glabrescent, not persistent; fruiting calyx accrescent in young fruit tightly investing the berry, the tube 3-5 mm long, later tearing and the berry exposed, the lobes 3-5 mm long, ca. 3 mm wide, appressed to spreading. Seeds ca. 40 per berry, 1.5-2 mm long, 1-1.7 mm wide, flattened and teardrop shaped with an apical hilum, reddish brown, the surfaces minutely pitted, testal morphology not clearly seen. Stone cells 10-11 per berry, 1-1.3 mm in diameter, globose, scattered throughout the berry. Chromosome number not known (but see comments on DNA content below).

Distribution

(Fig. 79 ). Solanum hunzikeri occurs in Argentina (Provs. Catamarca and Tucumán) and north to Bolivia (Depts. Chuquisaca and Tarija). The somewhat disjunct distribution is possibly due to loss or lack of the wet high elevation foggy grassland habitat in intervening areas. Most Argentine collections are from the Ambato area of endemism of Aagensen et al. (2012).

Ecology and habitat.

Solanum hunzikeri is confined to wet cloud forests and foggy grasslands above 1,800 m elevation; it also grows in the ecotones between these vegetation types.

Common names and uses.

None recorded.

Preliminary conservation status

( IUCN 2022). Near Threatened [NT]. EOO = 97,182 km2 [LC]; AOO = 80 km2 [EN]. Although the large extent of occurrence would suggest S. hunzikeri is not of conservation concern, the limited number of localities (<10), the specialised habitat and the disjunct distribution suggest the species should be considered as under some threat. Solanum hunzikeri occurs in a very restricted habitat in which there are few officially protected areas. In these landscapes the main threat to the ecosystem is over-grazing; the introduction of alien forage species has severely altered the nature of the high elevation foggy grasslands and forest edges in which S. hunzikeri occurs. Some populations are found in currently protected areas such as the Parque Nacional Aconquija, but these areas are considered too small and isolated to provide long term conservation ( Brown 1995). Knapp et al. (2020) assigned a preliminary threat status of Vulnerable (VU, B2a,b(iii)) for S. hunzikeri . The exploration of these relatively inaccessible habitats in the area between the currently known populations of S. hunzikeri is a priority.

Discussion.

Solanum hunzikeri was long recognised as distinct from other glandular-pubescent species in Argentina but has only recently been named ( Knapp et al. 2020) when additional specimens allowed us to clarify its differences from the widespread and highly variable S. tweedieanum . Solanum hunzikeri can be distinguished from S. tweedieanum populations in similar high elevation areas in its strongly attenuate and winged leaf bases; those of S. tweedieanum are more truncate. The single collection we have seen of S. hunzikeri with mature fruit ( Rodríguez 1421 from Salta) has the calyx not covering any part of the mature berry; berries of S. tweedieanum are tightly covered by the accrescent calyx for at least 50% of their length. Berries of S. tweedieanum are pale cream when ripe, while berry colour in S. hunzikeri is not known. More collections of S. hunzikeri in fruit are needed to assess these differences. Preliminary data on DNA content suggest that, like S. tweedieanum ( Moscone 1992), S. hunzikeri is diploid (F. Chiarini unpubl.).

Figures

Figure 77. Solanum hunzikeri A flowering stem B inflorescence C flower D open flower E immature fruit showing the accrescent calyx not completely covering the berry F flower showing pubescent adaxial surface of the filaments G calyx H gynoecium I stamen, ventral view J stamen, dorsal view K seed L stone cell (A-D, F-J Barboza 4763 E, K, L Hunziker & Subils 22205). Illustration by S. Montecchiesi. Previously published in Knapp et al. (2020: 41).

Figure 78. Solanum hunzikeri A leaf (adaxial surface) showing attenuate base B inflorescence C flower at anthesis D maturing infructescence with fruits enclosed in the enlarged calyx (A-D Barboza et al. 4763). Photos by M. Gritti. Previously published in Knapp et al. (2020: 39).

Figure 79. Distribution map of Solanum hunzikeri.