New Andean Species of Solanum Section Geminata (Solanaceae)

Abstract

Three new Andean species of Solanum sect. Geminata are described: S. youngii from Peru and Ecuador, S. quebradense from Venezuela, and S. habrocaulon from Peru. Relationships within section Geminata are discussed, and the species are illustrated. Solanum is one of the largest genera of flowering plants, with approximately 2000 valid species. Section Geminata (G. Don) Walpers (s.1.) is one of the largest subdivisions of the nonspiny solanums, with some 145 species. Members of the section are distinguished from other nonspiny solanums by their shrubby habit, small white flowers in leaf-opposed inflorescences, and hard green fruits at maturity. Section Geminata itself is composed of several smaller monophyletic groupings and is probably related to the Solanum nitidum species group and section Holophylla (G. Don) Walpers (s. str.). A key distinguishing these groups can be found in Knapp (1989). Most of the members of section Geminata grow in the understory of primary forest and are rare plants of limited distribution. All but one of the species of section Geminata are found in the Neotropics, with the highest concentration in the Andes and their foothills. These foothill areas are particularly rich in taxa of families that are primarily understory shrubs (Gentry, 1982), and species diversity of Solanum sect. Geminata is extremely high in the Andes (Knapp, 1986). Solanum youngii S. Knapp, sp. nov. TYPE: Ecuador. Zamora-Chinchipe: Parque Nacional Podocarpus, Loja-Zamora road just E of pass, ca. 2800 m, 3?58'S, 79007'W, 15 Mar. 1989, Madsen 85888 (holotype, QCA; isotype, AAU). Figure 1A, B. Frutex; caules dense pubescentes trichomatibus dendriticis; sympodia difoliata, geminata; folia elliptica vel ovata valde bullata subtus dense dendritico-pubescentia; corolla alba; bacca globosa in pedicello erecto portata; semina complanata reniformia. Shrubs, 1.5-2 m tall; young stems and leaves densely pubescent with matted dendritic trichomes to 1.5 mm long, the trichomes drying a rich golden brown; stems thick, erect; bark of mature stems dark gray. Sympodial units difoliate, geminate, occasionally appearing unifoliate through loss of the minor leaf. Leaves elliptic to ovate, widest at or just below the middle, thick and fleshy, strongly bullate and corrugated when dry, with 5-6 pairs of primary veins, sparsely to moderately pubescent with dendritic trichomes adaxially, densely pubescent with dendritic trichomes 1-1.5 mm long abaxially, the trichomes denser along the veins, major leaves 717 x 4-9.5 cm, the apex acute, the base decurrent onto the petiole; petiole 1.2-2 cm long; minor leaves differing from the majors only in size, 4-8 X 2-4 cm; petiole ca. 1 cm long. Inflorescences opposite the leaves, simple, 0.5-7 cm long, 5-40flowered, but bearing only a few flowers at a time, densely pubescent with dendritic trichomes like those of the stems and leaves. Pedicel scars closely spaced, obscured by the dense pubescence of the inflorescence axis. Buds globose, later elliptic, strongly exserted from the calyx tube. Pedicels at anthesis erect to somewhat deflexed, thick and fleshy, 0.8-1 cm long, pubescent with trichomes like the rest of the inflorescence. Flowers with the calyx tube broadly conical, 1-1.5 mm long, the lobes triangular and irregularly splitting, 1-4 mm long, with a tuft of dendritic trichomes at the tips, otherwise sparsely pubescent; corolla white, waxy, 1.7-2 cm diam., lobed ca. 2/3 of the way to the base, the lobes planar at anthesis, tips of the lobes with a tuft of dendritic trichomes ca. 0.5 mm long, the margins papillose; anthers 5-6 x 1-2 mm, poricidal at the tips, the pores lengthening to slits with age; free portion of the filaments ca. 0.5 mm long, the filament tube ca. 0.5 mm; ovary glabrous; style 7-9 mm long, glabrous; stigma bilobed, the surface minutely papillose. Fruit a globose, green berry, 1-1.2 cm diam.; fruiting pedicels erect and woody, ca. 2 cm long, ca. 1.5 mm diam. at the base, ca. 2.5 mm diam. at the apex, 1-2 stone cells occasionally present in the pericarp. Seeds dark brown, flattened reniform, 2-3 x 1.5-2 mm, the margins incrassate and paler, the surfaces minutely pitted. NovoN 6: 28-32. 1996. This content downloaded from 40.77.167.104 on Sat, 09 Apr 2016 06:42:21 UTC All use subject to http://about.jstor.org/terms Volume 6, Number 1 1996 Knapp Solanum Section Geminata 29