Three New Species of Solanum Section Geminata (G. Don) Walp. (Solanaceae) from Panama and Western Colombia

Abstract

Three new species of Solanum are described: S. darienense from eastern Panama, S. unifoliatum from the low elevation wet forests of the department of Choc6 in Colombia, and S. dolosum from higher elevations in the department of Valle de Cauca in Colombia. Relationships of these species are discussed. Solanum section Geminata (G. Don) Walp. is one of the largest sections of Solanum, with 82 species, most of these Neotropical. They are generally small trees and shrubs, often growing in primary forest understory, an unusual habit in Solanum. Characters useful in recognizing the section are 1) difoliate sympodial units with geminate leaf clusters or unifoliate sympodial units, 2) leaf-opposed inflorescences, 3) plants glabrous or with simple uniseriate trichomes, 4) small white or greenish-white flowers, and 5) hard, green fruits at maturity (see Knapp, 1985, 1986 for discussion of these characters). While preparing a monograph of the group, I encountered many new species, both in the field and in the herbarium. Three of these are described here so that the names can be used in floristic works. Solanum darienense S. Knapp, sp. nov. TYPE: Panama, Dari6n, Cana near Rio Setigandi, 540-580 m, 18 Apr. 1980, Gentry et al. 28541 (holotype, MO, location of isotypes unknown). Figure 1. Frutex; caulesjuniores sparse pubescentes, laete alati; caules veteres glabri, cortice nitido rubro-stramineo; nodi unifoliati;folia elliptica vel ovata utrinque glabra; apice acuto, basi truncata; inflorescentiae fohiis oppositae simplices filiformes minute puberulae; pedicelli sub anthesi filiformes deflexi; calycis lobi deltoidei minute puberuli; corolla alba lobis sub anthesi reflexis; bacca globosa viridis, pedicello frugifero deflexo ad apicem expanso; semina fusca ovoidea reniformia, testa foveolata. Shrubs with foetid foliage, 1-1.5 m tall; young stems sparsely hispidulous with erect uniseriate trichomes ca. 0.1 mm long, these often only on one side of the stem; young leaves glabrous; stems winged from the decurrent leaf bases; bark of older stems reddish-golden and shiny. Leaves elliptic to ovate, not geminate except on nonreproductive nodes, widest at or just below the middle, glabrous on both surfaces, occasionally minutely puberulent along the veins beneath, 1 114 cm long, 3-4.5 cm wide, with 7-8 pairs of primary veins, these not prominently raised above, prominent and yellowish beneath, the apex acute to acuminate, the base truncate; petioles winged from the decurrent leaf bases, ca. 1 mm long. Inflorescences opposite the leaves, simple, thread-like, 0.5-1.5 cm long, 4-5-flowered, minutely puberulent with erect uniseriate trichomes like those of the stems; pedicel scars evenly spaced 1-2 mm apart, slightly raised; pedicels at anthesis filiform, 0.6-1 cm long, tapering from the calyx to a slender base ca. 0.25 mm in diameter, sparsely puberulent with uniseriate trichomes; buds globose when young, hispidulous with uniseriate trichomes like those of the rest of the inflorescence, the corolla soon exserted from the calyx tube making the buds elliptic to obovoid; calyx tube broadly conical, ca. 0.5 mm long, the lobes deltoid, 0.25-0.5 mm long, the margins paler, the lobes and tube minutely hispidulous with uniseriate trichomes ca. 0.1 mm long; corolla white, 5-7 mm in diameter, lobed nearly to the base, the lobes reflexed at anthesis, the tips and margins of the lobes minutely papillose; anthers ca. 1.5 mm long, 1 mm wide, poricidal at I I thank James Mallet, W. G. D'Arcy, and Michael D. Whalen for advice and encouragement; Bente Starke King for the illustrations; and the curators of the following herbaria for the loan of specimens or the use of facilities, BH, COL, F, MO, NY, US. This research was funded by U.S. National Science Foundation grant BSR 8302773 to Michael D. Whalen and Sandra Knapp, and by an American Association of University Women Educational Foundation Fellowship to Sandra Knapp. 2 L. H. Bailey Hortorium, 467 Mann Library, Cornell University, Ithaca, New York 14853. ANN. MISSOURI BOT. GARD. 73: 738-744. 1986. This content downloaded from 207.46.13.153 on Fri, 05 Aug 2016 06:11:53 UTC All use subject to http://about.jstor.org/terms 1986] KNAPP-SOLANUM SECT. GEMINATA 739 FIGURE 1. Solanum darienense (from Gentry et al 28541), scale bar equals 1 cm. the tips, the pores becoming slit-like upon drying; free portion of the filaments 0.25-0.3 mm long, the filament tube ca. 0.1 mm long; ovary glabrous; style straight, 3-3.5 mm long; stigma a slight broadening at the top of the style, minutely papillose. Berries globose, green at maturity, ca. 1.5 cm in diameter; fruiting pedicels deflexed, woody, 1.8-1.9 cm long, expanded at the apex, 0.5-0.75 mm in diameter at the base; seeds dark brown in dry material, ovoid-reniform, 3-3.5 mm long, 2-2.5 mm wide, the surfaces minutely pitted. Chromosome number: not known. Distribution. In the low mountains of eastern Panama, the only collections are from the vicinity of the gold mine at Cana, from 500 to 600 m elevation. Figure 2. Solanum darienense is related to S. confine Dunal in DC., a species of the Andean foothills in eastern Peru, and to S. pertenue Morton & Standley of montane Costa Rica and western Panama. Solanum darienense is distinct from these two species in its reddish-golden bark, slightly winged stems, obtuse, slightly oblique leaf bases and generally glabrous leaves. The members of this species complex are all very similar, perhaps due to their primary forest habitat. D'Arcy (1973) recognized S. darienense as a new entity from Panama but, due to the paucity of material available at the time, did not describe it. The species may also occur in adjacent Colombia or in other parts of the range of low mountains on the Panama-Colpmbia border. Additional specimens examined. PANAMA. DARIEN. Vicinity of airstrip at Cana gold mine, 480 m, 29 Jul. 1976, Croat 37963 (MO); vicinity of Cana, 1,750 ft, 23 Jun. 1959, Stern et al. 477, 661 (MO, US). Solanum unifoliatum S. Knapp, sp. nov. TYPE: Colombia, Choc6, Municipio de Choc6, This content downloaded from 207.46.13.153 on Fri, 05 Aug 2016 06:11:53 UTC All use subject to http://about.jstor.org/terms 740 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 73