Solanum stipitatostellatum
Not known
Usambara Mountains, Tanzania, and high elevation areas in Kenya and Mozambique; growing in rainforest understory, open forest, forest edges or disturbed ground; 700-2000 m elevation.
Solanum stipitatostellatum has not been included in any molecular analyses to date, but it is almost certainly a member of the Old World clade (Levin et al., 2006) of subgenus Leptostemonum, and may be related to the similar S. zanzibarense.
Bitter, G. 1923. Solana Africana. IV. Repert. Spec. Nov. Regni Veg., Beih.. 16: 1-320.
Dammer, U. 1894. Solanum stipitatostellatum. In: Abh. Königl. Akad. Wiss. Berlin 1894: 63.
Dammer, U. 1895. Solanaceae. In: E.A. Engler, Die Pflanzenwelt Ost-Afrikas und der Nachbargebiete. C. Verzeichniss der bis jetzt aus Ost-Afrika bekannt gewordenen Pflanzen, pp. 351-356. Berlin, Germany.
Dammer, U. 1906. Solanaceae africanae I. Bot. Jahrb. Syst. 38: 176-196.
Jaeger, P.-M.L. 1985. Systematic studies in the genus Solanum in Africa. PhD thesis, University of Birmingham, United Kingdom.
Levin, R.A., N.R. Myers, & L. Bohs 2006. Phylogenetic relationships among the "spiny" solanums (Solanum subgenus Leptostemonum). Amer. J. Bot. 93: 157-169.
Vorontsova, M. S., and S. Knapp. 2010. Lost Berlin (B) types of Solanum (Solanaceae) – found in Göttingen (GOET). Taxon 59: 1585-1601.
Local Names. Tanzania: Mbuntwe (Greenway 4746), Mbuntu (Greenway 4885), Mtula (Doncarlos 7247) [all Kinshamb. language].
Solanum stipitatostellatum is a robust plant with almost entire reddish leaves, large inflorescences, prickles small or absent, and trichomes with stalks 0.1-0.4 mm long. The fruit is markedly elongate during development and becomes spherical at maturity. Solanum stipitatostellatum includes variable populations from across the Usambara area with different rainfall patterns. The corolla size ranges between 1.8-3 cm in diameter, and the majority of specimens have a pedunculate inflorescence with 4-10 flowers. Solanum stipitatostellatum as recognized here includes five of Dammer’s Tanzanian species with different corolla measurements (Dammer 1894, 1895, 1906). Bitter united S. glochidiatum, S. englerianum, S. scheffleri and S. kitivuense under S. kitivuense (1923), and Jaeger (1985) suggested that the K isotype of S. stipitatostellatum is a poorly grown form of S. kitivuense. We accept Jaeger’s species concept under the epithet ‘stipitatostellatum’ as S. stipitatostellatum was published a year earlier than S. kitivuense (Dammer 1894, 1895).
Care must be taken with identification of this species. Most S. stipitatostellatum herbarium material is currently held under the names S. englerianum, S. glochidiatum and S. kitivuense. Specimens annotated as “sp. near stipitatostellatum” are often of S. taitense. Solanum stipitatostellatum has some distribution overlap with S. taitense and both taxa have stalked trichomes, but S. stipitatostellatum has mature leaves 6-13 mm long (versus leaves 1.2-3(3.5) cm long in S. taitense) and 3-10 flowers per inflorescence (versus 1-3(3) flowers per inflorescence in S. taitense).
Solanum stipitatostellatum lies within the distribution range of S. zanzibarense and near the superficially similar S. cyaneopurpureum, S. inaequiradians, S. lamprocarpum, and S. usaramense. Solanum stipitatostellatum differs from S. zanzibarense by its corolla 1.8-3 cm in diameter (versus corolla 1.5-2 cm diameter in S. zanzibarense), anthers 6-8 mm long (versus anthers 4-6.5 mm long in S. zanzibarense), inconspicuous prickles less than 2 mm long if present (versus prickles over 2 mm long in S. zanzibarense), and trichomes with stalks 0.1-0.4 mm long (versus sessile or with stalks up to 0.1 mm long in S. zanzibarense). Solanum stipitatostellatum appears close to S. inaequiradians with its acuminate leaves and trichomes with midpoints that are sometimes elongated to 0.7 mm. It can be distinguished from S. inaequiradians by its calyx lobes that are shorter than the corolla in bud (versus calyx lobes longer than the corolla throughout bud development in S. inaequiradians), calyx 4-6 mm long in flower and 5-8 mm long in fruit (versus calyx 7-9 mm long in flower and 10-12 mm long in fruit in S. inaequiradians), and trichomes with midpoints that are usually shorter than the midpoints and never extend beyond 0.7 mm (versus midpoints 1-2 mm long on all parts of the plant in S. inaequiradians). Solanum stipitatostellatum differs from S. lamprocarpum by its corolla 1.8-3 cm in diameter (versus corolla ca. 1.7 cm in diameter in S. lamprocarpum), ovate subentire leaves (versus elliptic to obovate lobed leaves in S. lamprocarpum), and trichomes with reduced midpoints, occasionally elongated to 0.7 mm on the young stems (versus trichomes with midpoints 0.7-1 mm long throughout the plant in S. lamprocarpum). Solanum usaramense is easy to distinguish by its abundant uniform hooked prickles ca. 1 mm long, strongly discolorous leaves, and trichomes with stalks 0.2-0.3 mm long. Solanum cyaneopurpureum is also markedly different from S. stipitatostellatum with its yellowish color on herbarium specimens, leaves usually under 5 cm long, corolla under 2 cm in diameter, and anthers less than 6.5 mm long.