Solanum multiflorum
2n=24 (Krishnappa, D.G. and M. S. Chennaveeraiah. 1974. Cytotaxonomy of Solanum indicum complex. Cytologia 40: 323-331)
Solanum multiflorum is endemic to the Western part of Tamil Nadu Province in southern India, occurring in the Nilgiri, Coimbatore, Didingul and Madurai districts at forest edges and roadsides, 1700-2300 m elevation.
Solanum multiflorum has not been included in any molecular studies to date, but it likely to be placed close to S. violaceum Ortega in Old World clade, subgenus Leptostemonum (Levin et al., 2006).
Clarke, C.B. 1883. Solanum. In: Fl. Brit. India [J. D. Hooker] 4: 229-237.
Krishnappa, D.G. and M. S. Chennaveeraiah. 1974. Cytotaxonomy of Solanum indicum complex. Cytologia 40: 323-331.
Matthew, K.M. 1991. Precursory notes for a Flora of the Palni Hills, South India. Kew Bull. 46: 539-546.
Levin, R.A., N.R. Myers, & L. Bohs 2006. Phylogenetic relationships among the "spiny" solanums (Solanum subgenus Leptostemonum). Amer. J. Bot. 93: 157-169.
Roth, A.W. 1821. Novae plantarum species praesertim Indiae orientalis. Ex collectione doct. Benj. Heynii. Cum descriptionibus et observationibus. H. Vogler, Halberstadt, Germany.
Stafleu, F.A. & R.S. Cowan. 1983. Taxonomic Literature ed. 2. Vol. 4: P-Sak. Bohn, Scheltema and Holkema, Utrecht.
Wight, R. 1838-1853. Icones plantarum Indiae Orientalis: or figures of Indian plants. J.B. Pharoah, Madras, India.
Solanum multiflorum is a robust villous shrub with stout inflorescences, curved pedicels, and multiple yellow fruits on each inflorescence. This species encompasses two distinct morphotypes: the type collection of S. erosum and similar populations from Nilghiri and Coimbatore districts have finely divided leaves with secondary lobing and branched inflorescences, while more southern populations in Didingul and Madurai districts have larger leaves with simple lobes and long erect unbranched inflorescences. Most representatives of Solanum multiflorum have conspicuous long-acuminate calyx lobes. The easily visible trichomes on mature berries have caused it to be mistaken for the pubescent-fruited S. lasiocarpum Dunal.
Solanum multiflorum is closely related to the widespread S. violaceum. Solanum multiflorum largely replaces S. violaceum in montane forest regions above 1700 m although the two species are partly sympatric. Solanum multiflorum can be distinguished from S. violaceum by the trichomes on its pericarp persisting into maturity (and visible with the naked eye, versus pericarp always glabrous in S. violaceum), 10-20 fruits per inflorescence (versus 5-14 fruits per inflorescence in S. violaceum), woody recurved pedicels (versus slender straight pedicels in S. violaceum), anthers 3.5-4 mm long (versus anthers 4.5-8.5 mm long in S. violaceum), and trichomes with midpoints 0.7-1.8 mm long (versus trichomes with midpoints less than 1 mm long in S. violaceum). Karyotype analysis suggests that S. multiflorum is distinct from S. violaceum in the lengths of some chromosome arms and the presence of one pair of satellite chromosomes (although only one accession of S. multiflorum was analysed; Krishnappa and Chennaveeraiah 1974).
Another related Indian species is S. hovei Dunal, endemic to the Western Ghats (Maharashtra, Goa, and Kerala provinces) to the west and north of S. multiflorum’s distribution. Solanum hovei can be easily distinguished by its rhomboid leaves with acuminate lobes and moderate short indumentum; its karyotype includes two pairs of satellite chromosomes (only one accession of S. hovei was analysed; Krishnappa and Chennaveeraiah 1974).
Solanum multiflorum bears many similarities to S. usambarense Bitter & Dammer in Tanzanian and Kenyan mountains: both are higher elevation species with large villous leaves, larger inflorescences, and trichomes with elongated midpoints, replacing the lower altitude and fewer-flowered S. violaceum and S. anguivi, respectively. Solanum usambarense can be distinguished from S. multiflorum by its multiply branched inflorescences and short calyx lobes. It is likely that S. multiflorum and S. usambarense were under similar selection pressures in their evolutionary histories.
The frequently cited “Solanum multiflorum Roth, Nov. Pl. Sp. 130. 1821” is a later publication of Solanum multiflorum Roth ex Roem. & Schult. (1819), as Roemer and Schultes used Roth’s original manuscript (Stafleu and Cowan 1983). Clarke (1883) cites "var. multiflora Wight" as a variety of Solanum indicum L. and includes S. multiflorum Roem. & Schult. within it, effectively publishing the new combination Solanum indicum L. var. multiflorum (Roth ex Roem. & Schult.) C. B. Clarke. He also cites Wight’s plate 1400, which seems to correspond to Wight 1575, erroneously attributed by Nees to S. lasiocarpum (=S. ferox L.). Matthew (1991) interpreted Clarke’s "var. multiflora Wight" as a new name, Solanum indicum var. multiflorum Wight ex. C.B. Clarke, with the holotype Wight 1757 (K) and published the new combination Solanum violaceum Ortega subsp. multiflorum (C.B.Clarke) K.M.Matthew. Since the correct basionym is Solanum multiflorum Roth ex Roem. & Schult., Wight 1757 is not a type. The type of this species has most likely been destroyed, but the description provided by Roth (1821) is sufficient for identification and this name has an established history of application. A neotype will need to be designated.