Solanum hunzikeri Chiarini & Cantero, 2020

Knapp, Sandra, Chiarini, Franco, Cantero, Juan J. & Barboza, Gloria E., 2020, The Morelloid clade of Solanum L. (Solanaceae) in Argentina: nomenclatural changes, three new species and an updated key to all taxa, PhytoKeys 164, pp. 33-66 : 33

Solanum hunzikeri Chiarini & Cantero sp. nov. Figs 1A-C , 2

Diagnosis.

Like Solanum tweedieanum Hook. but differing in sessile leaves with broadly winged petioles, pedicels in flower longer than 1 cm, larger flowers and anthers more than 1 mm wide.

Type.

Argentina. Catamarca: Dtto. Ambato, Los Morteritos, Sierra de Ambato, falda E, subiendo desde El Rodeo hacia el Cerro Manchado [Cerro Manchao], 2300-2400 m, 13 Jan 1973, A.T. Hunziker & R. Subils 22205 (holotype: CORD [CORD00013086]).

Description.

Herb or subshrub from a woody base ca. 50 cm tall; 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 to shallowly toothed, (2-)4.5-14 cm long, (1.1-)2-7 cm wide, elliptic in outline, 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 2.5-4 cm long, opposite the leaves, unbranched but occasionally forked ( Rodríguez 1421), 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, perfect. 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, 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, opaque, the surface of the pericarp glabrous, thin, matte; 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; 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 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

(Figure 3 ). Solanum hunzikeri occurs in Argentina in the provinces of Catamarca and adjacent Salta and Tucumán and extends north to Bolivia in the departments of Tarija and Chuquisaca. The distribution is somewhat disjunct possibly due to loss of the wet high elevation foggy grassland habitat in the intervening areas.

Ecology and habitat.

Solanum hunzikeri is confined to wet cloud forests and foggy grasslands above 1800 m elevation; it also grows in the ecotones between these vegetation types. These foggy grasslands are dominated by tall grasses (e.g., Festuca hieronymi Hack., Cinnagrostis polygama Griseb., Elionurus muticus (Spreng.) Kuntze [ Poaceae ]) and shrubs (e.g., Baccharis spp., Stevia spp. [ Asteraceae ]). Solanum hunzikeri can also be locally frequent on open grassy terraces with scattered palms, in narrow valleys with the lower slopes covered in seasonally moist forest dominated by Parajubaea torallyi (C.Mart.) Burret ( Arecaceae ) and with abundant Podocarpus spp. ( Podocarpaceae ) and can be found on steep, stony slopes in undisturbed grassland areas.

Etymology.

This species is named in honour of the late Ing. Armando T. Hunziker of IMBIV in Córdoba, whose life work on the Solanaceae inspired a generation of solanologists, in both Argentina and globally.

Preliminary conservation status

( IUCN 2019). AOO (80 km2 - EN); EOO (97,627 km2 - LC). Although the large extent of occurrence would suggest S. hunzikeri is not of conservation concern, the limited number of localities, the specialised habitat and the disjunct distribution suggest the species should be considered at risk. 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 such as Pennisetum clandestinum Hochst. ex Chiov. ( Poaceae ) has severely altered the nature of the high elevation foggy grasslands and forest edges in which S. hunzikeri occurs. Although some populations are found in currently protected areas such as the Parque Nacional Aconquija, these areas are considered too small and isolated to provide long term conservation ( Brown 1995). Based on the area of occupancy, the number of localities (ca. 8) in a disjunct distribution and threats to the habitat, we assign a preliminary threat status of Vulnerable (VU B2a,biii) for S. hunzikeri . The exploration of these relatively inaccessible habitats in the area between the currently known populations of S. hunzikeri is a priority.

Notes.

Solanum hunzikeri had been recognized as distinct from other glandular-pubescent species in Argentina in the early 20th century by the German botanist Georg Bitter as "Solanum catamarcae", a name already occupied in Solanum ( S. catamarcae Bitter ex Brücher, a synonym of S. boliviense Dunal, see Spooner et al. 2019). Morton (1976) in his treatment of Solanum for Argentina, cited Sleumer 2259 as part of his concept of S. atriplicifolium and stated "This last appears to be a local form that has the petioles broadly winged nearly throughout instead of at the apex only. According to determinations by Dr. Sleumer this plant was given the unpublished name of " Solanum catamarcae " by Bitter." Morton annotated the sheet of Sleumer 2259 in US as " Solanum atriplicifolium var. sleumeri Morton HOLOTYPE" in 1971 but did not publish the infraspecific epithet; he also annotated Sleumer 2311 (US) as a paratype of the same.

The species is now known from a wider distribution, and additional specimens have clarified 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. More collections of S. hunzikeri in fruit are needed to assess these differences. Preliminary data on DNA content for S. hunzikeri and S. tweedieanum (F. Chiarini unpubl.) show differences but suggest that, like S. tweedieanum ( Moscone 1992), S. hunzikeri is diploid.

Additional specimens examined

(paratypes). Argentina. Catamarca: Dtto. Ambato, camino desde El Rodeo rumbo al Cerro el Manchado [Manchao], Falda El Morro, 2593 m, 24 Feb 2016, Barboza et al. 4703 (CORD); Dtto. Ambato, Sierra de Ambato (falda E), subiendo desde El Rodeo hacia el Cerro Manchado [Manchao], 2300 m, 23 Feb 1967, Hunziker 19073 (CORD, US); Dtto. Pomán, Rumbo al Cerro Manchado [Manchao], Sierra de Ambato, falda E, subiendo El Rincon hacia Las Casitas, rumbo al Cerro Manchado [=Cerro del Manchao], 2300-2500 m, 18 Feb 1970, Hunziker & Ariza 20319 (CORD); Dtto. Pomán, Rumbo al Cerro Manchado, Sierra de Ambato, falda E, subiendo El Rincon hacia Las Casitas, rumbo al Cerro Manchado [= Cerro del Manchao], 2300-2500 m, 18 Feb 1970, Hunziker & Ariza 20329 (CORD); Dtto. Ambato, Los Morteritos, Sierra de Ambato, falda E, subiendo desde El Rodeo hacia el Cerro Manchado [Manchao], Los Morteritos, 2300-2400 m, 13 Jan 1973, Hunziker & Subils 22205 (CORD); Dtto. Ambato, Los Morteritos, Sierra del Ambato, falda E, subiendo desde El Rodeo hacia el Cerro Manchado [Manchao], 2300-2400 m, 13 Jan 1973, Hunziker & Subils 22206 (CORD); Dtto. Andalgalá, Río Potrero, 2600 m, 13 Feb 1942, Rohmeder s.n. (LIL); Dtto. Andalgalá, Río Lampacillo-Río Potrero, Entre Río Lampacillo y Río Potrero, 2700-2900 m, 26 Feb 1951, Sleumer 1834 (LIL, US); Dtto. Andalgalá, Mesada La Primera, Mesada La Primera, Las Estancias, 1900 m, 11 Feb 1952, Sleumer 2132 (LIL); Dtto. Andalgalá, Los Queñoales, arriba de la Mesada de Las Rosas, 2300-2400 m, 15 Jan 1952, Sleumer 2259 (G, LIL, US); Dtto. Andalgalá, Cuesta de la Negrilla, cerca de la Mina de Capillas, 3000-3100 m, 2 Mar 1952, Sleumer 2690 (CORD, G, US); Dtto. Andalgalá, Cuesta de la Negrilla cerca de la Mina de Capillitas, 3100 m, 2 Mar 1952, Sleumer 2691 (CORD, G, US, W); Dtto. Andalgalá, Mina de las Capillitas, cerca de los edificios, 2350 m, 2 Jan 1952, Sleumer 2692 (US, W). Salta: Dtto. Cafayate, Peñas Blancas, Cerros de Cajón [Sierras de Quilmes], 4040 m, 30 Mar 1914, Rodríguez 1421 (BR, CORD, SI). Tucumán: Dtto. Alberdi, Escaba, 2300 m, 27 Dec 1913, Monetti 1838 (LIL); Dtto. Alberdi, Estancia Yunka Suma, Valle del Río Las Chacras [as Catamarca, Dtto. Andalgalá on labels], 1800 m, 23 Feb 1951, Sleumer 1610 (LIL); Dtto. Alberdi, Cumbres de Suncho, Quebraditas del Portezuelo Sta. Anna [as Catamarca, Dtto. Andalgalá on labels], 2150 m, 8 Feb 1952, Sleumer 2311 (LIL, US).

Bolivia. Chuquisaca: prov. Zudañez, a 82 km de Sucre, entre Tarabuco y Sudanéz, paraje Lambayo, 2756 m, 25 Feb 2004, Cocucci et al. 3357 (CORD); prov. Azurday, Tarvita, ca. 3 km S of summit on road from Tarvita to Azurduy, 2800 m, 4 Dec 1999, Wood et al. 15303 (K); prov. Tomina, ca. 1 km W of summit of pass between Villa Tomina and Villa Serrano, 2700 m, 17 Mar 2002, Wood 17868 (K); prov. Azurduy. Bajando de la cumbre hacia Duraznal en el camino de Azurduy, 2459 m, 11 Dec 2004, Wood & Huaylla 21130 (K); prov. Tomina, entre Villa Serrano y Tomina, en la cumbre, 2580 m, 4 Mar 2006, Wood et al. 22394 (K); prov. Zudañez, AMNI El Palmar, AMNI El Palmar, along trail from Torotoro to El Palmar crossing Río Mission Waypu., 2800 m, 2 Feb 2007, Wood et al. 22612 (K). Tarija: Sama, between Tarija and Villazón, 3546 m, 27 Feb 1939, Balls 6111 (E, K, US); de Tarija a Narváez, 2000-2500 m, 19 Mar 1982, Kiesling et al. 3734 (SI); de Tarija a Iscayachi, 2000-3000 m, 20 Mar 1982, Kiesling et al. 3845 (SI); Mun. O’Connor, at the top of the first pass W of Entre Ríos on road to Narváez and Tarija, 1800 m, 21 Jan 2001, Wood & Goyder 16901 (K).

Cultivated.

Argentina. Córdoba: IMBIV, Universidad Nacional de Córdoba [plant grown from Barboza et al. 4703], 450 m, 15 Feb 2017, Barboza 4763 (CORD).

Figures

Figure 1. Solanum hunzikeri Chiarini & Cantero (A-C) compared to S. tweedieanum Hook. (D-F) and S. physalidicalyx Bitter (G-I) A habit (Barboza et al. 4763) B calyx morphology of developing fruits (Barboza et al. 4763) C leaf from mature stem (Barboza et al. 4763) D habit (Barboza et al. 3496) E calyx morphology of developing fruits (Barboza et al. 4798) F leaf from mature stem (Barboza et al. 4798) G habit (Barboza et al. 3983) H calyx morphology of developing fruits (Barboza et al. 3983) I leaf from mature stem (Barboza et al. 3983). Photos A-C, E, F by M. Gritti, D by S. Knapp, G-I by G. E. Barboza.

Figure 2. Solanum hunzikeri Chiarini & Cantero 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 style with pubescence confined to the portion inside the anther cone I adaxial surface of the anther showing the pores elongating with age J abaxial surface of the anther K seed L stone cell (sclereid).

Figure 3. Distribution of Solanum hunzikeri Chiarini & Cantero.