2n=24 (Federov 1969)
Southeastern Madagascar; dry scrub and roadsides; 0–500 m elevation.
Solanum pyracanthon was one of the first three spiny Solanum species from Madagascar to be included in molecular phylogenetic studies (Bohs, 2005) and is a member of the Old World clade of subgenus Leptostemonum (Levin et al. 2006). It belongs to the somewhat well-supported Madagascar Clade of Vorontsova et al. (2013), in a group with Solanum erythracanthum and Solanum myoxotrichum.
Solanum pyracanthos is a striking ornamental species with prominent orange prickles and dark orange to red venation on the leaves that creates a bright contrast with green leaves, vivid purple flowers and yellow anthers. Solanum pyracanthos attracted the attention of science about 50 years earlier than any other species of Solanum from Madagascar. It was grown from seed at the Paris Botanical Gardens before Lamarck described it in 1794. Attention of the horticultural trade was captured, and the species became widely cultivated. Color illustrations of S. pyracanthos were published by Jacquin (1804) from a plant of unknown origin at the Schoenbrunn Gardens in Austria, by Wendland (as S. runcinatum, 1798) from a plant recorded as originating from India, and by Smith (1804) from a plant cultivated in Britain. It is still widely grown for ornament in the northern hemisphere, often in glasshouses or as a seasonal shrub in more temperate areas.
Solanum pyracanthos is a morphologically uniform species unlikely to be confused with another taxon. Its closest relative is most likely S. erythracanthum because of their shared simply lobed leaves and tendency towards reddish indumentum. Solanum pyracanthos is more robust and woody, with mature leaves often resembling those of dandelions (Taraxacum, Asteraceae), and larger fruit than S. erythracanthum.
The specific epithet was originally published as “pyracanthos,” a Greek noun in apposition not correctable to an adjective; the alternative forms “pyracanthon” and “pyracanthum” are thus incorrect.
Of the two specimens of S. pyracanthos in the Lamarck herbarium we have chosen (P00357689) as the lectotype, despite it only having fruit and buds. The other sheet (P00357690) and possible isolectotype has open flowers, but does not have an label linking it to the protologue. The leaves of both specimens are very similar, however, and are likely from the same plant.
Bohs, L. 2005. Major clades in Solanum based on ndhF sequences. Pp. 27-49 in R. C. Keating, V. C. Hollowell, & T. B. Croat (eds.), A festschrift for William G. D’Arcy: the legacy of a taxonomist. Monographs in Systematic Botany from the Missouri Botanical Garden, Vol. 104. Missouri Botanical Garden Press, St. Louis.
D’Arcy, W.G., & A. Rakotozafy 1994. Solanaceae. Famille 176, pp. 1-146. In Flore de Madagascar et des Comores, P. Morat (ed.). Muséum National D’Histoire Naturelle, Paris.
Federov, A.A. 1969. Chromosome numbers of flowering plants. 926 pp. Academy of Sciences U.S.S.R., Moscow.
Jacquin, N.J. 1804. Plantarum rariorum horti caesarei schoenbrunnensis descriptiones et icones. C. F. Wappler, Vienna.
Levin, R.A., N.R. Myers, & L. Bohs 2006. Phylogenetic relationships among the "spiny" solanums (Solanum subgenus Leptostemonum). Amer. J. Bot. 93: 157-169.
Smith, J.E. 1804. Exotic botany: consisting of coloured figures, and scientific descriptions, of such new, beautiful, or rare plants, as are worthy of cultivation in the gardens of Britain; with remarks on their qualities, history, and requisite modes of treatment. Volume two. R. Taylor and Co., London.
Vorontsova, M. S., S. Stern, L. Bohs, and S. Knapp. 2013. African spiny Solanum (subgenus Leptostemonum, Solanaceae): a thorny phylogenetic tangle. Bot. J. Linn. Soc. 173: 176-193. doi:10.1111/boj.12053
Wendland, J.C. 1798. Botanische Beobachtungen, nebst einigen neuen Gattungen und Arten. Gebrüdern Hahn, Hannover.
Local Names. Madagascar: Kokomba, rohingivy, vangivy, vontaka (D’Arcy and Rakotozafy 1994).
Uses. Ornamental plant cultivated in glasshouses worldwide.