Citation:
Brittonia 44: 65. 1992.
Type:
Bolivia. Tarija: 15.8 km E of Narváez on road to Entre Ríos (12.5 km W of Entre Ríos), 1650 m, 21 28'S, 64 12'W, 4 Oct 1983, Solomon 11045 (holotype, NY; isotype, MO).
Last edited by:
Knapp, S.
Written by:
Knapp, S.
Habit:
Shrubs ca. 2 m tall; young stems and leaves densely arachnoid-pubescent, the trichomes fine, delicate and dendritic, the leaves and stems soon glabrate; bark of older stems dark reddish-brown.
Sympodial structure:
Sympodial units unifoliate.
Leaves:
Leaves elliptic to narrowly elliptic, widest at the middle, with 9-12 pairs of main lateral veins (reddish abaxially), glabrous and shiny adaxially, with a few arachnoid trichomes abaxially, especially along the midrib, 9-14 cm long, 4-5 cm wide, the apex acute to acuminate, the base attenuate; petioles 1.5-1.6 cm long.
Inflorescences:
Inflorescences opposite the leaves, simple, 1-1.3 cm long, sparsely pubescent with floccose arachnoid trichomes along the axis, especially near the apex; pedicel scars closely spaced, not overlapping. Buds rounded when young, later ellipsoid, very strongly exserted from the calyx tube. Pedicels at anthesis slender, more or less deflexed, 1.5-2.5 cm long, ca. 0.5 mm in diam., glabrous or occasionally sparsely pubescent with arachnoid trichomes.
Flowers:
Flowers with the calyx tube broadly cup-shaped, nearly flat, 1-1.5 mm long, the lobes minute, broadly deltate, 0.25-0.5 mm long, very sparsely pubescent with arachnoid trichomes; corolla white, 0.8-1.5 cm in diam., divided ca. 3/4 of the way to the base, the lobes planar at anthesis, the tips and margins of the lobes minutely papillose; anthers 3-3.5 mm long, ca. 1 mm wide, poricidal at the tips, the pores tear-drop shaped; free portion of the filaments ca. 0.25 mm long, the filament tube ca. 0.25 mm long; ovary glabrous; style straight, ca. 5 mm long; stigma clavate, the surface minutely papillate.
Fruits:
Fruit not known.
Seeds:
Seeds not known.
Chromosome number:
Not known
Distribution:
In southern Bolivia and northwestern Argentina, in subtropical moist forest at ca. 1600-1700 m elevation.
Phylogeny:
Solanum platycypellon is a member of the Solanum nigricans species group (Knapp, 2002) of the Geminata clade (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.
Taxonomic name:
Solanum platycypellon is closely related to S. maturecalvans, also of Andean distribution. It differs from that species in its unifoliate sympodial units, smaller flowers and flatter, more open calyx tube. Solanum maturecalvans is a plant of higher elevations, while S. platycypellon occurs in subtropical moist forest at somewhat lower elevations.
The arachnoid pubescence typical of members of the Solanum nigricans species group is very soon deciduous in S. platycypellon, but is always present on the new growth and the tips of the inflorescence axes. Solanum platycypellon may be a synonym of S. kieslingii, but the latter has distinct triangular calyx lobes, while the calyx of these speciemsn is quite distinct. Further field study is necessary to resolve this issue.