Solanum schulzianum
Citation:
Symb. Ant. 5: 488. 1908.
Type:
Dominican Republic. Jimenes, 1190 m, Jun, H. Eggers 2208 (syntype, B destroyed?; isosyntype, K [K000196492]); Puerto Plata, Monte Isabel de la Torre, 770 m, H. Eggers 1668 (syntype, B destroyed?).
Written by:
Knapp, S.
Habit:
Shrub to 2 m, armed; stems sparsely to densely prickly with yellowish acicular prickles 0.5-1 cm long, sparsely pubescent with sessile or very short-stalked porrect stellate trichomes to 0.5 mm with 3-5 rays, the midpoints to 0.5 mm; new growth glabrous or sparsely stellate pubescent, sparsely to densely prickly, extremely variable; bark of older stems reddish brown, shiny.
Sympodial structure:
Sympodial units plurifoliate.
Leaves:
Leaves simple, 8-16 x 3.5-7 cm, elliptic to lanceolate-elliptic in outline, membranous or chartaceous, the upper surface glabrous and shiny, sparsely to densely prickly with prickles to 1 cm on veins and lamina, the lower surface sparsely stellate pubescent with sessile porrect trichomes with 4 rays, the midpoints ca. 0.5 mm long; primary veins 5-8 pairs, yellowish and prominent on both surfaces; base attenuate; margins shallowly lobed to almost pinnatifid 0.4-1.5 cm from the midrib, the lobes equal in number to the veins, 0.5-3 cm long; apex acute; petiole 0.8-2 cm, glabrous to sparsely stellate pubescent like the stems.
Inflorescences:
Inflorescences opposite the leaves or internodal, 7-30 (+) cm long, simple, with 30-100 flowers but only a few open at a time, sparsely stellate pubescent or glabrous, sometimes with a few yellowish prickles near the base; peduncle 3.5-4 cm; pedicels 0.5-1.3 cm, relatively stout, ca. 1 mm in diameter at the apex, ca. 0.5 mm in diameter at the base, nodding at anthesis (?), glabrous or sparsely stellate pubescent, articulated at the base; pedicel scars widely spaced 1-1.5 cm apart. Buds globose then ellipsoid, included in the calyx until just before anthesis.
Flowers:
Flowers apparently heterostylous; calyx tube 1.5-2.5 mm, cupuliform, the lobes 1.5-3 mm, linear or long-triangular, the sinuses hyaline, sparsely pubescent with scattered stellate trichomes like those of the rest of the inflorescence, with yellow acicular prickles to 4 mm on lobes and tube; corolla 1.5-2 cm in diameter, deep red-violet (fide Ekman 12268) or purple, stellate or somewhat pentagonal, lobed ½ to 3/4 of the way to the base, the lobes 0.8-1 x 0.3-0.4 cm, planar at anthesis, glabrous adaxially, densely pubescent abaxially with minute porrect stellate trichomes with reduced rays, even in almost glabrous individuals; anthers 6-6.5 x 1.5-2 mm, elongate and tapering to poricidal tips, the pores not elongating into slits; free portion of the filaments 1-1.5 mm, the anthers spreading, the filament tube ca. 0.5 mm, glabrous; ovary conical, glabrous; style in long-styled flowers ca. 1 cm, in short-styled flowers ca. 4 mm, glabrous in both; stigma capitate to somewhat 2-lobed, the surfaces minutely papillate.
Fruits:
Fruit a globose berry, 1-1.5 cm in diameter, the pericarp thin and shiny, glabrous; fruiting pedicels 1-5-2 cm, somewhat woody, ca. 1-2 mm in diameter at the base; calyx lobes in fruit to 8 mm.
Seeds:
Seeds ca. 25 per berry, 3-4 x 2-3 mm, flattened reniform, pale tan, the surfaces minutely pitted, the testal cells rectangular with slightly sinuate margins.
Chromosome number:
Not known
Distribution:
Known only from the eastern portion of the island of Hispaniola (currently collections only seen from the Dominican Republic) growing in forests from 300-1300 m elevation.
Phylogeny:
Solanum schulzianum is a member of the Leptostemonum clade (Weese & Bohs, 2007); in Whalen’s (1984) classification it was considered to have uncertain affinities, but to be close to S. lomense (as S. lomensis) and S. urens, two other species of unknown affinities.
References:
Whalen, M.D. 1984. Conspectus of species groups in Solanum subgenus Leptostemonum.
Gentes Herbarum 12 (4): 179-282.
Weese, T.L. & L. Bohs 2007. A Three-Gene Phylogeny of the Genus Solanum (Solanaceae)
Syst. Bot. 32(2): 445-463.
Solanum schulzianum is extremely variable in both prickliness and in leaf shape. Leaves vary from almost simple with a very shallowly toothed margin (e.g. Ekman H.12268) to almost pinnatifid (e.g., Ekman H.5012). The stems vary from nearly prickle-free to densely prickly, and this may be in part related to plant age, with more juvenile plants being more prickly. Flowers are said to be dark purple to reddish, an unusual color in Solanum. Judging for the number of collections, S. schulzianum is not rare where it occurs, although it is of extremely restricted distribution.
Solanum schulzianum is very similar to S. selleanum, also from Hispaniola. The two species share deeply lobed to pinnatifid leaves, densely prickly stems and leaf surfaces and elongate, whip-like inflorescences with flowers in the distal half. Without looking closely at the pubescence and calyx morphology the species are almost identical on the herbarium sheet, but S. schulzianum has sparser leaf pubescence of porrect stellate trichomes with few rays and purple flowers, while S. selleanum has densely pubescent leaf undersides with a combination of porrect stellate trichomes with 8-10 rays and a dense fine covering of sessile stellate trichomes and white flowers. Solanum selleanum has broadly deltate calyx lobes rather than the distinctive long-triangular lobes with prominent sinuses of S. schulzianum. The calyx of S. selleanum appears to be dark purple, while that of S. schulzianum is green or whitish green. The taxa grow at similar elevations and in similar pine wood habitat and are probably closely related.
The long, whip-like inflorescence of S. schulzianum is shared with several other Caribbean endemic Solanum species, e.g., S. selleanum, S. chamaeacanthum, S. miragoae and S. gundlachii.
Of the two syntypes cited in the original description, only Eggers 2208 is fertile; the Kew duplicate of this collection is therefore a logical choice for a lectotype.