Solanum multifidum
Citation:
Tabl. Encycl. 2: 17. 1794.
Type:
Peru. Dombey (holotype, P-LA)
Last edited by:
Bennett, J.
Written by:
Bennett, J.
Habit:
Annual, erect or prostrate herb up to 50 cm tall. Stems fleshy, becoming woody, up to 12 mm in diameter at the base, glabrous or rarely sparsely pubescent with simple, uniseriate, multicellular hairs up to 0.6 mm long.
Sympodial structure:
Sympodial units difoliate or rarely plurifoliate, not geminate.
Leaves:
Leaves pinnate, bipinnate or rarely tripinnate, fleshy, the blades 4.0–16 (–19) x 1.4–7.5 cm, 1.6–2.7 (–3.2) times as long as wide, usually with a narrow wing 1–6 mm wide along the midrib between the primary pinnae, glabrous adaxially and abaxially or rarely sparsely to moderately pubescent adaxially and abaxially with simple, uniseriate, multicellular hairs up to 1 mm long (Arequipa and Tacna specimens only); base decurrent on a winged petiole, the wing up to 10 mm wide and extending beyond the leaf node and forming a flange running parallel to the stem; margin divided into 3–6 pairs of primary pinnae, the primary pinnae 4–30 (–48) x 3–22 (–46) mm, usually asymmetrically arranged each side of the midrib, decreasing in size from base of leaf to the apex, primary pinnae divided further into 1–3 secondary and occasionally tertiary pinnae irregularly spaced along each side, secondary and tertiary pinnae 2–20 x 1–8 mm; apex of all pinnae acute to obtuse; petioles indistinct, winged.
Inflorescences:
Inflorescences 4.5–20 cm long, borne on terminal and axillary shoots, branched 1–2 (–3) times, with 8–32 flowers, all flowers perfect, the axes subglabrous to moderately pubescent, the hairs often appressed, simple, uniseriate, unicellular or multicellular, up to 1.5 mm long; peduncle 1.7–7 (–12.5) cm long; pedicels 5–11 mm at anthesis, 11–25 mm in fruit, spaced 4–10 mm apart in fruit, articulated at the base.
Flowers:
Flowers with the calyx 3.3–5.5 mm long, the tube 0.6–2.0 mm, the lobes equal, 1.8–3.8 x 0.5–1.5 mm at anthesis, 2.2–4.2 x 1.0–1.8 mm in fruit, oblong, becoming ovate in fruit, the apex obtuse, glabrous adaxially and abaxially or rarely sparsely pubescent abaxially with simple, uniseriate, multicellular hairs up to 0.4 mm long. Corolla 11–16 mm in diameter, pentagonal to rotate, white, sometimes turning light blue, purple, or violet, the tube ca. 1 mm long, the lobes 7–10 x 5.5–8.5 mm, subglabrous to densely pubescent abaxially with white, simple, uniseriate, unicellular or multicellular hairs up to 1.0 mm long, glabrous adaxially. Stamens 5, equal; filament tube ca. 1.0 mm long, glabrous; filaments equal, 1.0–1.5 mm long, glabrous; anthers equal, 3.0–4.2 x 0.6–1.2 mm, oblong, yellow, not connivent, poricidal at the tips, the pores tear-drop shaped, rapidly opening into longitudinal splits the entire length of the anther with age. Ovary glabrous; style 4.5–7.0 x 0.1 mm, cylindrical, straight, glabrous; stigma clavate, 1.4–2.5 x 0.9–1.0 mm.
Fruits:
Fruit 4.0–6.5 (–10) mm in diameter, globose, green, turning red when ripe, glabrous, pendant, stone cells absent.
Seeds:
Seeds 1.0–1.1 x 1.1–1.2 mm, obovate, flattened, pale brown, the surface shallowly pitted.
Distribution:
Coastal Peru in the Departments of Ancash, Arequipa, Ica, La Libertad, Lima, Moquegua and Tacna. On arid sandy soil and dunes, rocky and gravelly hillsides. 0–1200 m in elevation.
Phenology:
Flowers July to March.
Phylogeny:
This species belongs to the Regmandra clade of Bohs (2005), an isolated clade within the non-spiny solanums.
References:
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 multifidum is similar to the Chilean species S. remyanum, but is restricted to Peru. It may be distinguished by the usually glabrous leaves and the winged leaf bases that extend beyond the leaf node and in some cases may form a broad and conspicuous flap of tissue. There are a small number of specimens collected from the southernmost part of its range from the departments of Arequipa and Tacna that are intermediate between the typical forms of S. remyanum and S. multifidum. The leaf bases of these specimens are less prominently winged (although not as distinctly petiolate as specimens of S. remyanum), the pinnae are narrower, and the leaves are sparsely or moderately pubescent. However, the indumentum is not as dense as that found on specimens of S. remyanum. I have maintained these as two separate species as there is usually no difficulty in assigning the majority of specimens to one or the other species based on the indumentum and form of the petiole, and there is no geographic continuity between the two species. A similar trend in increasing indumentum density with increasing latitude can be seen in S. montanum and S. paposanum.