Solanaceae Source

A global taxonomic resource for the nightshade family

Solanum pinnatum

Citation author: 
Cav.
Citation: 
Icones (Cavanilles) 5: 23. 1799.
Type: 
Chile. Coquimbo, Née s.n. (type, MA [656494]).
Last edited by: 
Bennett, J.
Written by: 
Bennett, J.
Habit: 
Perennial, erect shrub 30–200 cm tall. Stems pale brown, brittle, woody, glabrous to moderately pubescent with simple, uniseriate, multicellular hairs up to 0.25 mm long.
Sympodial structure: 
Sympodial units unifoliate, not geminate.
Leaves: 
Leaves simple, fleshy, the blades 1.3–8.0 x 0.8–5.6 cm, 1.2–2.0 (–2.7) times as long as wide, subglabrous to moderately or occasionally densely pubescent adaxially and abaxially with simple uniseriate, multicellular hairs up to 0.5 mm long; base decurrent; margin regularly lobed with 3–5 pairs of lobes, the lobes 3–24 x 1–9 mm, 1.8–5.0 times as long as wide, dentate or serrate, elliptic to ovate, the basal and apical sides of the lobes convex; the lobe apex acute to rounded; petioles 0–20 mm, with indumentum as that of leaf blades.
Inflorescences: 
Inflorescences 3–17 cm long, borne on terminal and axillary shoots, branched 2–3 times, with 12–30 (–40) flowers, all flowers perfect, the axes subglabrous to densely pubescent with appressed, simple, uniseriate, multicellular hairs up to 0.6 mm long; peduncle 0.5–12 cm; pedicels 3–8 mm at anthesis, 5–10 mm in fruit, spaced 3–5 mm apart in fruit, articulated at the base.
Flowers: 
Flowers with the calyx 3–5 mm long, the tube 0.8–3.0 mm, the lobes equal, 2.0–4.2 x 0.6–1.0 mm at anthesis, 2.0–3.0 x 1.5–1.7 mm in fruit, elliptic to ovate, the apex acute to rounded, subglabrous to densely pubescent adaxially and abaxially with simple, uniseriate, multicellular hairs up to 0.3 mm long. Corolla 12–20 mm in diameter, pentagonal, chartaceous, white, violet, purple or blue, the tube 1–3 mm long, the lobes 6–10 x 5.5–12 mm, moderately to densely pubescent abaxially, especially in bud and towards the lobe apices, the hairs simple, uniseriate, multicellular, up to 0.4 mm long, glabrous adaxially. Stamens 5, equal; filament tube 1.0–1.2 mm, glabrous; filaments equal, 1.0–2.0 mm long, glabrous; anthers equal, 3.0–4.5 x 1.0–1.5 mm, oblong, yellow, not connivent, poricidal at the tips, the pores tear-drop shaped and opening into longitudinal slits with age. Ovary glabrous; style 5–6 x ca. 0.2 mm, cylindrical, straight, glabrous; stigma capitate or clavate, 0.9–1.0 x 0.6–0.8 mm.
Fruits: 
Fruit 3–4 mm in diameter, globose, glabrous, green, few-seeded, stones cells present, abundant, rounded, ca. 0.5 mm diameter.
Seeds: 
Seeds 1.4–1.5 x 1.6–1.8 mm, flattened, pale brown, glabrous, the surface shallowly pitted.
Chromosome number: 

Not known

Distribution: 

Endemic to Chile [Regions I (Tarapacá), II (Antofagasta), III (Atacama), IV (Coquimbo), V (Valparaíso), VI (Liberador), VIII (Bío-Bío), Metropolitana. On dry, sandy or rocky coastal slopes and dunes, 3–2300 m in elevation.

Phenology: 
Flowers April to February.
Phylogeny: 

This species belongs to the Regmandra clade of Bohs (2005), an isolated clade within the non-spiny solanums.

Commentary: 

Solanum pinnatum is a morphologically variable species from Chile. The leaf shape and indumentum are particularly variable, ranging from small, narrowly dissected leaves with the pinnae almost needle-like (such as those of the type of S. maritimum) to much larger and more rounded lobes such as those of the type of S. novemlobum. An examination of a large number of specimens has shown that leaf size and shape are continuously varying characters and cannot be divided into discrete taxa. Consequently, a large number of previously described species are here placed in synonymy.

The species can be recognised by the singly lobed leaves and usually dense inflorescences. The calyx and filaments are shorter than those of another Chilean species with lobed leaves, S. paposanum. Solanum paposanum also differs by its densely velutinous indumentum and narrowly acute apices to the leaf lobes. The fruits of S. pinnatum are unusual among species of section Regmandra because they contain a very small number of seeds; the majority of the fruit contents consists of stone cells. The low seed set (< 5 seeds per fruit) is particularly intriguing given how widespread this species is, particularly around Coquimbo and Valparaíso, in Chile.

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.

Wed, 2013-11-20 11:02 -- sandy
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith