Solanum oblongifolium
Citation:
Solan. syn. 14. 1816.
Type:
Colombia. Caldas: Quindio, Humboldt & Bonpland s.n. (holotype, P-Bonpl.; isotypes, P [Morton neg. 8269], frag. F).
Last edited by:
Knapp, S.
Written by:
Knapp, S.
Habit:
Shrubs or small trees, 2-20 m tall; young stems and leaves variously pubescent with loose, translucent dendritic trichomes ca. 1 m long; the stems thick, erect, often winged from the decurrent leaf bases; bark of older stems pale greenish-yellow.
Sympodial structure:
Sympodia plurifoliate, often with much axillary branching, giving the stems a bushy appearance.
Leaves:
Leaves elliptic to obovate, often very large, especially on juvenile plants, widest at or just above the middle, the lamina glabrous adaxially or occasionally sparsely pubescent with dendritic trichomes, the pubescence dense along the veins, abaxial surface densely to sparsely pubescent (a few collections glabrous) with translucent dendritic trichomes 1-2 mm long, these denser along the veins; blades 9-30 x 4-15 cm, with 15-20 pairs of main lateral veins, these drying yellowish abaxially, the apex acute to acuminate, the base acute to sessile with the basal portion of the leaf winged onto the stem and crotaloid; petiole 0-1.5 cm long, if leaves sessile, always winged onto the stems.
Inflorescences:
Inflorescence terminal, later lateral, 5-25 cm long, many times branched, up to 15 cm across, 20-200-flowered, the pubescence like that of the stems; pedicel scars unevenly spaced 1-2 mm apart. Buds globose, later obovoid, strongly exserted from the calyx tube. Pedicels at anthesis stout, erect, 0.2-1 cm long, 1-1.5 cm in diam., densely or sparsely pubescent with translucent dendritic trichomes.
Flowers:
Flowers with the calyx tube broadly conical, 1.5-2.5 mm long, the lobes broadly deltate with a prominent knob ca. 0.3 mm from the apex, 0.3-1 mm long, densely or sparsely pubescent like the rest of the inflorescence, the apex always possessing a tuft of simple translucent trichomes; corolla white, fleshy, 1.2-2 cm in diam., lobed nearly to the base, the lobes with large thin margins, planar at anthesis, the tips and distal margins of the lobes densely papillate; anthers 3-4 mm long, 1-2 mm wide, poricidal at the tips, the pores tear-drop shaped; free portion of the filaments 0-0.5 mm long, the filament tube 0-0.5 mm long, glabrous; ovary glabrous; style stout, barely surpassing the anther cone, ca. 5 mm long; stigma capitate, the surface minutely papillose.
Fruits:
Fruit a globose, green or yellowish-green berry, the pericarp hard and woody, 1.5-2.5 cm in diam.; fruiting pedicels woody, erect, 0.8-1.1 cm long, ca. 5 mm in diameter.
Seeds:
Seeds pale tan, flattened-reniform with a prominent incrassate margin, 3.5-5 mm long, 3-3.5 mm wide, the body of the seed flat, the margins minutely pitted.
Chromosome number:
Not known
Distribution:
Common in secondary growth at high elevations in the Andes from Venezuela to northern Peru, 2000-3500 m.
Phylogeny:
Solanum oblongifolium is a member of the Solanum oblongifolium species group of the Geminata clade (Knapp, 2002; Bohs, 2005).
References:
Knapp, S. 2002. Solanum section Geminata (G. Don) Walpers (Solanaceae).
Flora Neotropica 84: 1-405.
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.
Solanum oblongifolium is a very common shrub at middle to high elevations and usually grows in open places along roadsides or pastures. It is most closely related to S. venosum, with which it is sympatric in at least part of its range. Solanum oblongifolium differs from S. venosum in its transparent trichomes which are always dendritic, never tree-like as are those of the stems of S. venosum. The flowers of S. oblongifolium are borne in very large inflorescences, however these are often not collected as they are difficult to press. The petals are quite waxy and the flowers have a sweet fragrance, unusual in the section (but see S. validinervium in the amblophyllum group and S. corumbense in the leucocarpon group).
Leaf base morphology varies considerably throughout the range of Solanum oblongifolium and has no obvious geographical component. Leaves vary from petiolate with the petioles to 3 cm long to sessile with the leaf bases somewhat auriculate. In these latter plants, the leaf base has been termed "crotaloid", because when dry it resembles a rattlesnake's tail (see S. crotalobasis Bitter, a synonym of S. maturecalvans Bitter of the nigricans group, named for its similar leaf bases).
Plants from northern Peru are generally larger than those from the rest of the species range. They have been called var. soukupii Macbride. Some hybridization may occur between Solanum hypaleurotrichum and S. oblongifolium in Ecuador. Specimens of this type are listed with S. hypaleurotrichum (see above) and are generally closer to S. hypaleurotrichum in overall morphology than to S. oblongifolium, but possess abaxial leaf surface trichomes that are intermediate between the two species.
In lectotypifying Solanum jamesonii, I have chosen Jameson 627 from the syntypes at BM as Jameson 625 is a mixed collection with a member of section Torva (Solanum hispidum Pers.). Both sheets are annotated in Bitter’s hand.