Solanum alliariifolium M.Nee & Saerkinen, 2015

Saerkinen, Tiina, Knapp, Sandra & Nee, Michael, 2015, Two new non-spiny Solanum species from the Bolivian Andes (Morelloid Clade), PhytoKeys 47, pp. 97-109 : 98-99

Solanum alliariifolium M.Nee & Saerkinen sp. nov. Figs 1 , 2

Diagnosis.

Similar to Solanum leptocaulon Van Heurck & Müll.Arg., but differing in its slender creeping habit with stems rooting along nodes, broadly ovate to orbicular leaves with mostly undulate to shallowly lobed margins, and a stellate corollas lobed to the middle with lobes reflexed at anthesis.

Type.

Bolivia. Santa Cruz. Prov. Vallegrande: 6.5 km by air SW of Guadalupe on rd to Pucará, at turnoff to Santa Ana, 18°36'S, 64°07'W, 2675 m, 15 Dec 1990 (fl,fr), M. Nee 40315 (holotype: LPB; isotypes: MO [MO-2537105], NY [NY00852828], USZ).

Description.

Slender herb to 20-30 cm high, with multiple long, creeping stems arising from a central taproot. Stems rooting at nodes, 1-2 mm in diameter, up to 50 cm long, glabrous or sparsely pubescent with spreading translucent 4-6-celled simple uniseriate trichomes ca. 0.2 mm long. Sympodial units difoliate, not geminate. Leaves simple, 1.5-3.6 cm long, 0.9-2.3 cm wide, broadly ovate to orbicular; adaxial surface glabrous; abaxial surface glabrous or sparely pubescent with appressed 1-3-celled simple uniseriate trichomes along veins and leaf margins; primary veins 3-4 pairs; base rounded to attenuate, occasionally decurrent; margins entire, undulate, or shallowly lobed; apex acute; petiole 0.7-1.5 cm long, sparsely pubescent with simple 1-3-celled uniseriate trichomes like those of the stems, especially on young leaves. Inflorescences 1.5-3.0 cm long, simple, lateral, leaf-opposing or internodal, with 2-6 flowers, sparsely pubescent with simple uniseriate 4-6-celled spreading trichomes; peduncle 1.0-3.0 cm long, 0.4-0.5 mm in diameter at the apex and 0.6 mm in diameter at the base; pedicels 0.6-0.9 cm long, ca. 0.4 mm in diameter at the base and ca. 0.5 mm in diameter at the apex, straight and spreading at anthesis, articulated at the base; pedicel scars spaced 0.2-1.5 mm apart. Buds globose, white or purple-tinged. Flowers 5-merous, all perfect, nodding; calyx tube ca. 1.4-1.5 mm long, the lobes 1.6-2.0 mm long, rectangular-deltate in outline with rounded to acute apices, somewhat spreading at anthesis, sparsely pubescent with simple 1-4-celled uniseriate trichomes; corolla 1.4-1.6 cm in diameter, white to pale or deep violet-blue, with a dark purple ring and yellow-green central star at the base, stellate, lobed to the middle, the lobes ca. 4.0-5.0 mm long, 2.0-2.5 mm wide, reflexed at anthesis, densely pubescent abaxially with 1-2-celled simple uniseriate trichomes, these usually shorter than the trichomes of stems and leaves, glabrous adaxially; filament tube 1.3-1.5 mm long; free portion of the filaments ca. 1.1-1.6 mm long, pubescent with 4-7-celled uniseriate trichomes at the base adaxially; anthers 3.5-4.0 mm long, 0.8-1.0 mm wide, ellipsoid to rectangular in outline, yellow, poricidal at the tips, the pores lengthening to slits with age; ovary globose, glabrous; style 5-6 mm long, exerted 1.0-1.7 mm beyond the anther cone, densely pubescent with 2-3-celled simple uniseriate trichomes in the basal 2/3; stigma clavate, minutely papillate. Fruit a globose berry, 4-5 mm in diameter, green when developing, the colour when mature unknown, with a few stone cell aggregates in each berry; fruiting pedicels 1.1-3.2 cm long, ca. 0.4 mm in diameter at the base, ca. 0.6 mm in diameter at the apex, spreading, becoming somewhat woody; fruiting calyx lobes 2.8-3.2 mm long, spreading. Seeds 15-20 per berry, ca. 1.5-1.7 mm long, ca. 1.2-1.3 mm wide, flattened, reniform, pale-brown, the sub-lateral hilum positioned close to the middle, the testal cells pentagonal in outline.

Distribution.

Endemic to montane forests of the Eastern Bolivian Andes in the Departments of Chuquisaca, Cochabamba, and Santa Cruz, in open areas close to water sources, near rivers and moist depressions, and marshy meadows on sandy or rocky substrates, associated with Podocarpus parlatorei Pilg., Alnus acuminata Kunth, Hesperomeles ferruginea (Pers.) Benth., Alchemilla pinnata Ruiz & Pav., Azorella biloba (Schltdl.) Wedd., Weinmannia fagaroides Kunth, Baccharis genistelloides (Lam.) Pers., Clethra scabra Pers., Myrsine coriacea (Sw.) Roem. & Schult., Symplocos nana Brand, Eleocharis spp., Chusquea spp., Morella pubescens (Willd.) Wilbur, ferns, grasses and Apiaceae herbs; between 1,900 and 3,200 m elevation.

Ecology.

Flowering and fruiting during the wet season, generally from October-March, with a single record known from August.

Etymology.

The epithet refers to the leaf shape, which struck the collector of the type (MN) as like that of Alliaria petiolata (M.Bieb.) Cavara & Grande ( Brassicaceae ), a European species invasively adventive in the eastern USA and other temperate areas of the world.

Conservation status.

We assign a preliminary IUCN threat status of Vulnerable (VU, B1) to Solanum alliariifolium based on the small extent of occurrence (EOO=16,136 km2). The area of occupancy is even smaller (AOO=40 km2) and would merit status as endangered (EN), but knowing that collection densities in the tropical Andes remain extremely low and that the collections are mainly along the sparse road network, we prefer basing our assessment on the extent rather than area of occurrence. No occurrences are known within the protected area network in Bolivia thus far, but collection data indicates that the species endures grazing pressures relatively well.

Specimens examined.

Bolivia. Chuquisaca: Prov. Belisario Boeto: ca. 5 km S of Nuevo Mundo at summit of rd to Villa Serrano, 2,300 m, 18 Oct 1997, J.R.I. Wood 12710 (K). Prov. Hernando Siles: Primera Sección Monteagudo, Cantón Fernández, Comunidad Vallecito, 20°12'43"S, 64°18'03"W, 2,314 m, 11 Aug 2007, M. Jiménez 603 (NY); Laguna Milagros, 20°17'16"S, 64°02'56"W, 1,993 m, 26 Dec 2005, R. Lozano & M. Serrano 1787 (MO, NY); Primera Sección Monteagudo, Cantón Fernández, Comunidad Vallecito, 20°12'18"S, 64°17'58"W, 2,456 m, 9 Nov 2007, J. Villalobos 927 (MO). Cochabamba: Prov. Carrasco: Siberia, 17°49'87"S 64°44'07"W, 2,940 m, 20 Feb 2005, S. Altamirano & M. Alcázar 3075 (MO); Sehuenka-Totora, 2,800 m, Nov 1959, M. Cárdenas 5716 (US); Jatum Pino, 3200 m, Jan 1961, M. Cárdenas 5942 (K); near Lagunillas (Totora), 2,700 m, Jan 1951, M. Cárdenas 4663 (US); narrow canyon of Rio Monte Puncu, 5 km NE of Monte Puncu, 10 km by air NW of Epizana, 17°33'S, 65°16'W, 2,700- 2,750 m, 10 Mar 1988, M. Nee 36631 (NY); de Episana a Sehuancas via Montepunca, 2,500 m, 25 Mar 1978, C.M. Ochoa 12022 (US); 5 km above Sehuencas towards Monte Puncu, 2,500 m, 4 Feb 1995, J.R.I. Wood 9317 (K). Santa Cruz: Prov Caballero: 5.5 km (by rd) E of town of El Churro at pond along Pojo-Comarapa highway, 17°50'15"S 64°44'00"W, 2,940 m, 22 Jan 2006, M. Nee & Jun Wen 53903 (MO, USZ). Prov. Vallegrande: Huasacañada, 5 km al S de la ciudad de Vallegrande, 18°31'30"S 64°05'42"W, 2,050 m, 3 Nov 1990, I. Vargas C. 787 (MO, NY, USZ); carretera entre Vallegrande y Pucará, 18°35'49"S 64°07'34"W, 2,673 m, 5 Mar 2005, J.R.I. Wood 21774 (K, USZ).

Discussion.

Solanum alliariifolium is distinct within the Morelloids in being a slender creeping herb rooting at the nodes, with broadly ovate to orbicular leaves with undulate to shallowly lobed margins. It is morphologically most similar to Solanum leptocaulon Van Heurck & Müll.Arg., which occurs in similar montane habitats in Bolivia and in southern Peru, but the latter species is a small scrambling shrublet with ovate-lanceolate leaves with entire margins. Solanum leptocaulon further differs from Solanum alliariifolium in having a campanulate corolla lobed only 1/3 of the way to the base, rather than a stellate corolla lobed to 2/3 to the base with the lobes clearly reflexed at anthesis.

Figures

Figure 1. Illustration of Solanum alliariifolium. A Habit B Inflorescence with details of indumentum of simple, multi-cellular hairs along the stem, and short ciliate hairs along leaf margins C Flower just before anthesis, with and without corolla lobes removed D Flower at anthesis E Stamens F Gynoecium G Fruit (A-C, E-G Nee 40315, D Vargas 787). Illustration by Bobbi Angell.

Figure 2. Distribution map of Solanum alliariifolium.