Solanum delicatulum
Citation:
Phytologia 10: 424. 1964.
Type:
Brazil. Santa Catarina: Itajaí, Cunhas, 10 m, 8 Feb 1955, Klein 1131 (holotype, HBR not seen; isotype frag. US [US00027002]).
Last edited by:
Knapp, S.
Written by:
Knapp, S.
Habit:
Herbs to subshrubs to small shrubs 0.5-1.5 m; stems slender and erect, more or less densely pubescent with a mixture of simple and branched (dendritic) uniseriate trichomes ca. 0.5 mm, the trichomes closely appressed and ascending; bark pale yellowish; new growth desnsely pubscent like the stems with a mixture of simple and branched trichomes, especially on the veins.
Sympodial structure:
Sympodial units difoliate, usually geminate, but occasionally the leaf pair distant, some nodes occasionally trifoliate.
Leaves:
Leaves simple, differing in size and shape, adaxially glabrous to sparsely pubescent on the veins and lamina with a mixture of simple and dendritic trichomes ca. 0.5 mm, abaxially sparsely to densely pubescent on the veins, more sparsely pubescent on the lamina, the trichomes simple or furcate-dendritic, ca. 0.5 mm; major leaves 3-7 x 1.4-3 cm, elliptic to ovate, the base acute, the margins entire, the apex acute; primary veins 6-7 pairs, drying yellowish; petioles 0.4-1 cm, glabrous to sparsely pubescent; minor leaves 1.5-2 x 1-1.6 cm, similar in shape to the majors but usually somewhat more orbicular, the base acute, the margins entire, the apex acute; petioles 0.2-0.4 cm.
Inflorescences:
Inflorescences internodal or somewhat leaf-opposed, 0.2-0.5 cm, simple, with 2-3 flowers, sparsely pubescent with a mixture of trichomes like those of the stems, the peduncle 0.1-0.2 cm; pedicels 0.5-0.6 cm, less than 0.5 m in diameter at the base, ca. 1 mm in diameter at the apex, nodding at anthesis; pubescent with simple and dendritic trichomes like those of the stems and inflorescences; pedicel scars closely spaced, overlapping at the tip of the inflorescence, plane with the rachis. Buds globose, the corolla included in the calyx lobes.
Flowers:
Flowers all perfect; calyx tube 1-1.5 mm, open-conical, the lobes 2-2.5 mm, long-triangular, sparsely pubescent with simple uniseriate trichomes; corolla 0.9-1 cm in diameter, white, lobed ca. 3/4 of the way to the base, the lobes 0.7-0.9 cm, deltate, planar to slightly reflexed at anthesis, glabrous or sparsely pubescent with scattered trichomes along the petal midveins and tips adaxially; filaments with the free portion ca. 0.5 mm, the tube less than 0.5 mm, glabrous; anthers 2-2.5 x ca. 1 mm, poridical at the tips, the pores lengthening to slits with age; ovary conical, glabrous, the style 4-5 mm, straight, glabrous, the stigma 2-lobed to bifid, the surfaces minutely papillate.
Fruits:
Fruit a globose berry, 1-1.2 cm in diameter, red-orange at maturity, the pericarp thin and brittle; fruiting pedicels 0.5-0.7 cm, ca. 1 mm in diameter at the base, woody and erect.
Seeds:
Seeds 3-4 x 2-3 mm, flattened reniform, yellowish tan, the margins thickened, the surfaces minutely pitted.
Distribution:
Brazil (Santa Catarina and São Paulo) and Argentina (Misiones and Corrientes), forests and forest edges at ca. 800 m.
Phylogeny:
Solanum delicatulum is a member of the Solanum pseudocapsicum species group of the Geminata clade (sensu Bohs, 2005). It is part of a complex of taxa closely related to Solanum pseudocapsicum.
References:
Knapp, S. 2002. Solanum section Geminata (G. Don) Walpers (Solanaceae).
Flora Neotropica 84: 1-405.
Mentz, L.A. & P.L. de Oliveira 2004. Solanum (Solanaceae) na região sul do Brasil.
Pesquisas, Bot. 54: 1-327.
Gutiérrez, A., G.E. Barboza & L.A. Mentz 2006. Solanum delicatulum (Solanaceae): nueva cita para Argentina y Paraguay y su sinonomía.
Darwiniana 44(2): 508-513.
Solanum delicatulum was excluded from section Geminata (it was thought to be a member of section Solanum or a related group), and S. pavimenti included in the synonymy of Solanum pseudocapsicum by Knapp (2002). Subsequent studies by L. A. Mentz (Mentz & Oliveira, 2004) of this rare species have shown that it is a member of the section, and a member of the S. pseudocapsicum group with bright red fruit, and pedicels nodding in flower and erect in fruit. Some authors (G.E. Barboza, pers. comm.; Gutiérrez et al., 2006) distinguish S. pavimenti and S. delicatulum as distinct based on a suite of fruit and leaf characters that I feel are part of the overall variation in S. delicatulum.
Studies by Gutiérrez et al. (2006) show that S. delicatulum is relatively widespread in Argentina and Brazil, and occurs sporadically in E Paraguay. It is a plant of understory in forests and along streams, and can be assessed as of Near Threatened (NT) or Vulnerable (VU), depending upon the circumscription of the species (as including S. pavimenti, as defined here or excluding it, as delimited by Gutiérrez et al., in press).