Solanum amnicola
Citation:
Brittonia 38: 295. 1986.
Type:
Peru. Pasco: km 28 Repartición-Iscozacín (km 86 Villa Rica-Iscozacín-Puerto Mairo), Río La Raya near Amuesha community of Laguna, ca. 350 m, 10 20'S, 75 10'W, 22-23 Aug 1984, Knapp & Mallet 6651 (holotype, BH; isotypes, K, NY, US, USM).
Last edited by:
Knapp, S.
Written by:
Knapp, S.
Habit:
Shrubs growing along the rocky, gravelly, or sandy banks of streams and rivers, 0.5-1.5 m tall; young stems and leaves minutely and densely red-papillose; older stems glabrate; bark greyish, faintly longitudinally striate.
Sympodial structure:
Sympodial units usually difoliate, geminate, occasionally plurifoliate.
Leaves:
Leaves narrowly elliptic to obovate, widest at the middle or just above, glabrous above, minutely golden-puberulent along the veins beneath, the trichomes unicellular and barely visible, blades 11-20 x 1-4 cm, with 6-10 pairs of main lateral veins, these impressed above, yellowish beneath in dry specimens, the apex long-acuminate, the base attenuate; petioles winged from the decurrent leaf bases, 1.5-2 cm long.
Inflorescences:
Inflorescences opposite the leaves or sometimes internodal, 1-4 cm long, occasionally branched once, bearing 3-5 flowers at a time, but with many scars, glabrous or minutely red-papillose at the tip; pedicel scars closely spaced but not overlapping, beginning at the base of the inflorescence. Buds ellipsoid even when very young, the corolla not early exserted from the tube; pedicels at anthesis deflexed, 0.8-1 cm long, tapering from the base of the calyx tube to a slender base ca. 0.4 mm in diam.
Flowers:
Flowers with the calyx tube broadly cup-shaped, 1-1.5 mm long, the lobes deltoid, 1-2.5 mm long, the margins white and thickened in dry material, minutely puberulent along the margins and tips of the lobes; corolla white, 0.8-1 cm in diam., lobed nearly to the base, the lobes planar or slightly reflexed at anthesis, the tips and margins of the lobes minutely papillose; anthers 2-2.5 x ca. 1 mm, poricidal at the tips, the pores tear-drop shaped; free portion of the filaments ca. 0.5 mm long, the filament tube ca. 0.25 mm long; ovary glabrous; style straight, 5-6 mm long; stigma capitate, bi-lobed, minutely papillose.
Fruits:
Fruit a globose, green berry, 1-1.2 cm in diam.; fruiting pedicels erect and woody, 1.5-1.7 cm long, ca. 1 mm in diam. at the base; calyx lobes slightly woody and accrescent in fruit, 3-5 mm long.
Seeds:
Seeds pale brownish-green, ovoid-reniform, 2-3 x 1.5-2 mm, the surfaces minutely pitted.
Distribution:
On the banks of streams and rivers in eastern Peru at low elevations, from Amazonas south to Cuzco.
Phylogeny:
Solanum amnicola is a member of the Solanum arborreum 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.
Solanum amnicola is morphologically extremely similar to S. monadelphum, also a shrub of river banks in eastern Peru. Solanum amnicola can be distinguished from S. monadelphum by its slender leaf-opposed inflorescences, long-acuminate calyx lobes, smaller flowers, and the minute golden trichomes along the veins on the underside of the leaves. Solanum monadelphum is much more common than S. amnicola where the two occur in sympatry. Solanum amnicola is known from only a few localities, but is probably found throughout eastern Peru and only rarely collected.