Solanum taitense
Citation:
Linnaea 43: 327. 1882.
Type:
KENYA. Coast: Teita District, between Ndi and Tsavo River, Feb 1877, J. M. Hildebrandt 2605 (lectotype, designated by Vorontsova & Knapp 2010: GOET! [GOET009227]).
Last edited by:
Sandra Knapp (May 2014)
Written by:
Maria S. Vorontsova & Sandra Knapp
Habit:
Erect to scandent herb to shrub, 0.3-1.5 m, unarmed to weakly prickly. Young stems terete, densely stellate-pubescent and unarmed to weakly prickly, with porrect, variously stalked trichomes, the stalks to 0.1 mm long, the rays ca. 8, 0.1-0.2 mm long, the midpoints shorter than the rays, the prickles up to 1(-2) mm long, 0.2-0.5 mm wide at base, curved, brown or gray, glabrous, spaced 2-10 mm apart; bark of older stems glabrescent with persistent trichome stalks, dark gray.
Sympodial structure:
Sympodial units difoliate, not geminate.
Leaves:
Leaves simple, the blades 1.2-3(-3.5) cm long, 0.6-1.3 cm wide, 2-3 times longer than wide, ovate to elliptic, chartaceous, drying concolorous to weakly discolorous, yellow-green to red-green; adaxial surface densely stellate-pubescent, with thick-stalked trichomes; abaxial surface densely stellate-pubescent, with porrect, stalked trichomes, the stalks 0.1-0.15 mm long, thick, the rays ca. 8, 0.1-0.25 mm long, the midpoints ca. same length as the rays or shorter, unarmed on both surfaces; the primary veins not visible or 3-5 faint pairs, the tertiary venation not visible to the naked eye; base rounded to obtuse, sometimes cordate; margins subentire to entire; apex rounded; petiole 0.3-0.8 cm long, 1/6-1/4 of the leaf blade length, densely stellate-pubescent, unarmed.
Inflorescences:
Inflorescences apparently terminal or lateral, 1.2-2 cm long, not branched, with 1-2(-3) flowers, 1(-2) flowers open at any one time, densely stellate-pubescent, unarmed; peduncle absent; pedicels 0.7-1 cm long, erect, articulated at the base, densely stellate-pubescent, unarmed; pedicel scars spaced 1-4 mm apart.
Flowers:
Flowers 5-merous, apparently all perfect. Calyx 4-5 mm long, densely stellate-pubescent, unarmed, the lobes 2-3.5 mm long, deltate, apically acute to acuminate. Corolla 1-1.7 cm in diameter, white or purple, stellate, lobed for ca. 4/5 of the way to the base, the lobes 4.5-7 mm long, 1.5-2 mm wide, lanceolate to oblong, reflexed or spreading, densely stellate-pubescent abaxially, the trichomes porrect, subsessile, the rays ca. 8, 0.15-0.2 mm long, the midpoints shorter than the rays. Stamens equal, with the filament tube ca. 0.7 mm long, the free portion of the filaments ca. 0.1 mm long; anthers 4-6 mm long, spreading, tapering, poricidal at the tips. Ovary densely stellate-pubescent in the upper 1/5; style 0.6-1 cm long, filiform, straight or curved towards the tip, densely stellate-pubescent in the lower 2/3-3/4.
Fruits:
Fruit a spherical berry, 1-2 per infructescence, 0.6-1 cm in diameter, the pericarp smooth, red at maturity, glabrous; fruiting pedicels 1.3-1.6 cm long, 0.3-0.5 mm in diameter at base, herbaceous, pendulous, unarmed; fruiting calyx lobes not elongating, ca. 2/3 the length of the mature fruit, reflexed, unarmed.
Seeds:
Seeds ca. 10-20 per berry, ca. 3 mm long, ca. 2.6 mm wide, flattened-reniform, dull yellow to orange-brown, the surface smooth or with raised outlines of cells or small pits.
Chromosome number:
Not known
Distribution:
Kenya and Tanzania; growing in bushland and grassland on sandy soil or black clay soil; 0-1500 m elevation.
Phenology:
Flowering and fruiting throughout the year.
Phylogeny:
Solanum taitense has not been included in any molecular analyses to date, but it is almost certainly a member of the Old World clade within subgenus Leptostemonum (Levin et al., 2006), perhaps related to the morphologically similar Solanum hastifolium.
References:
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.
Solanum taitense is a medium-sized shrub recognized by its apically rounded subentire leaves, sparse inconspicuous prickles under 1(2) mm long, frequent branching, rarely more than 2 flowers per inflorescence, and relatively small corollas and short anthers. Trichomes on the adaxial sides of the leaf have short, dilated stalks, and the rays are reduced in size and pointing upwards.
Solanum taitense is partly sympatric with S. hastifolium and identification can be difficult due to the variable nature of the latter. No single morphological character separates all the specimens, but S. taitense has the majority of the following characters; entire to subentire leaves 1.2-3(3.5) cm long (versus lobed leaves 2.6-6.5 cm long in S. hastifolium), inconspicuous prickles up to 1(2) mm long (versus abundant prickles 1-4 mm long, spaced 3-10 mm apart in S. hastifolium), 1-2(3) flowers per inflorescence (versus 3-5 flowers per inflorescence in S. hastifolium), corolla 1-1.7 cm in diameter (versus corolla 1.4-2 cm in diameter in S. hastifolium), anthers 4-6 mm long (versus anthers 5-8 mm long in S. hastifolium), plant densely pubescent (versus plant sparsely to moderately pubescent in S. hastifolium), and stalked trichomes on all vegetative surfaces with inflated trichome stalks on the adaxial side of the leaves (versus trichomes sessile to shortly stalked in S. hastifolium). Solanum setaceum occurs to the south of S. taitense with limited range overlap; S. setaceum can be identified by the bristles over 2.5 mm long on its young stems. Solanum taitense has frequently been confused with the S. cyaneopurpureum due to shared small subentire leaves, highly branched form and stalked trichomes. The distribution ranges of these species do not overlap as S. cyaneopurpureum is found further east in Uganda and western Tanzania to the Democratic Republic of Congo. Solanum taitense can be distinguished from S. cyaneopurpureum by its rounded leaf apices (versus acute or sometimes obtuse leaf apices in S. cyaneopurpureum) and inflorescences with 1-2(3) flowers (versus inflorescences with 3-10 flowers in S. cyaneopurpureum).