Solanum megalonyx
Not known
Solanum megalonyx is endemic to Brazil, occurring in Bahia, northern Minas Gerais and Sergipe in campos rupestres, restingas and forest edges, from 0-800 m.
Solanum megalonyx is a member of the Leptostemonum clade (sensu Levin et al., 2006; Weese & Bohs, 2007) based on overall morphology, but its relationships have not yet been tested using molecular data. Whalen (1984) placed it in his S. erythrotrichum group, but with a question mark, indicating his uncertainty as to this placement. Agra (2004) places this species in her subsection Erythrotrichum.
Whalen, M.D. 1984. Conspectus of species groups in Solanum subgenus Leptostemonum.
Gentes Herbarum 12 (4): 179-282.
Agra, M.F. 2004. Sinopse Taxonômica de Solanum sect. Erythrotrichum (Solanaceae).
Pages 192-211, in Rangel-Ch, J.O; Aguirre-C, J.; Andrade-C., M.G. & Giraldo-Cañas (Eds). Memorias octavo congreso Latinoamericano Y Segundo Colombiano de Botánica. Instituto de Ciencias Naturales.
Levin, R.A., N.R. Myers, & L. Bohs 2006. Phylogenetic relationships among the "spiny" solanums (Solanum subgenus Leptostemonum).
Amer. J. Bot. 93: 157-169.
Weese, T.L. & L. Bohs 2007. A Three-Gene Phylogeny of the Genus Solanum (Solanaceae)
Syst. Bot. 32(2): 445-463.
Solanum megalonyx as delimited here can be recognised by its shrubby habit, strongly armed stems and trunk, few-flowered inflorescences, deeply lobed calyx and violet corolla to 3.5 cm in diameter. Pubescence and leaf shape are both highly variable, and a grade exists from the coast inland going from the littoral to the caatinga. Specimens collected in coastal habitats (e.g., Martius s.n., Scardino et al. 305, Noblick 1925) have larger corollas with longer lobes, larger subrhomboid to ovate-lanceolate leaves with the upper surfaces subscabrous and glabrescent, and trichomes with very short rays ca. 1/6 the length of the midpoint. More inland specimens (e.g., Carvalho & Thomas 3103, Carvalho & Plowman 1530, Queiroz & Fraga 3295, Arbo et al. 767, Chautems et al. 148) have more variable pubescence and leaf shape. The leaves are smaller than those from coastal populations, with less lobed and angulate margins, the pubescence is densely villous or tomentose with glandular stellate to multangulate trichomes with a shorter 1-2-celled midpoint. In some collections (e.g., Mori et al. 11111) entire and lobed leaf margins are found on the same plant. The other end of the extreme occurs in plants from the caatingas, which have smaller corollas with narrower lobes (e.g., Agra & Giulietti 5177, Arbo et al 7444), elliptic to ovate-elliptic leaves with velutinous and rusty pubescence of glandular porrect stellate trichomes with a midpoint the same length as the lateral rays. Looking at the extremes of this variation might lead one to think they were different taxa, but the variation is continuous and many intermediates exist.
Solanum megalonyx resembles S. cordifolium and S. jabrense, with which it shares simple inflorescences with large (ca. 3 cm diameter) purple flowers. Solanum cordifolium has more strongly cordate leaf bases and lobed glandular leaf margins, viscid pubescence of mixed simple and porrect stellate trichomes with glandular tips, larger, longer corolla lobes, and smaller seeds (2-3 mm in diameter). Solanum jabrense has acicular yellowish golden prickles on the leaves of adult plants, scabrous to tomentose pubescence that leaves the lamina visible, smaller flowers (ca. 2.5 cm in diameter), and is a plant of the high elevation brejo habitat.
Two sheets of Pohl 3224, the type collection of S. subcordatum, are present at W. The sheet chosen as the lectotype by Agra (2004) is more complete, with flowers and fruit, and is represented in many herbaria with copies of F negative 33114.