Solanum viarum
Solanum douglasii
tropical soda apple
Douglas' nightshade, greenspot nightshade
petiolate;
petiole 3–6 cm;
blade simple, ovate to suborbiculate, 7–10(–20) × 6–8(–15) cm, margins coarsely lobed with 3–5 lobes per side, lobe margins entire to coarsely toothed, base truncate to cordate.
petiolate;
petiole 0.5–3(–7) cm;
blade simple, ovate, 1–5(–9) × 0.5–3(–6) cm, margins entire to coarsely and irregularly toothed, base truncate to acute and decurrent.
extra-axillary, sessile or nearly so, unbranched, 3–5-flowered.
extra-axillary or leaf-opposed, unbranched, racemelike, 2–7(–14)-flowered, 2–4 cm.
0.7–1.1 cm in flower, 1–2 cm in fruit.
0.5–1 cm in flower and fruit, nodding or deflexed downward in fruit.
radially symmetric;
calyx somewhat accrescent, unarmed or sparsely prickly, 3–4 mm, densely pubescent, lobes triangular;
corolla greenish or whitish, stellate, 1.5–2.5 cm diam., without interpetalar tissue;
stamens equal;
anthers narrow and tapered, 5.5–7(–10) mm, dehiscent by terminal pores;
ovary densely pubescent, hairs glandular and eglandular.
radially symmetric;
calyx not accrescent, unarmed, 2–3 mm, sparsely pubescent, lobes deltate;
corolla white with yellow-green to brownish central star, stellate, 1–2 cm diam., without interpetalar tissue;
stamens equal;
anthers ellipsoidal and slightly tapered towards the tips, (2.5–)3–4.5 mm, dehiscent by terminal pores that open into longitudinal slits;
ovary glabrous.
light green mottled with dark green when young, yellow when ripe, globose, (1.5–)2–3 cm diam., glabrous, without sclerotic granules.
dull purplish black, globose, 0.5–1 cm diam., glabrous, with (2–)6–8 sclerotic granules per fruit.
reddish brown, flattened, 2–3 × 2–2.5 mm, minutely pitted.
pale yellow to tan, flattened, 1.5–2 × 1–1.5 mm, finely reticulate.
= 24.
= 24.
Solanum viarum
Solanum douglasii
In the United States, Solanum viarum was first collected in Florida in 1988 and has subsequently become an aggressive and invasive species in the Southeast. It is on the Federal Noxious Weeds List and is classified as a noxious weed or plant pest in many states. Cattle and other animals eat the fruits and spread the seeds through their feces, and the seeds are coated with a sticky substance that makes them adhere to farm equipment when the plants are mowed. It can form large patches that are difficult to eradicate due to their extensive root systems and sharp prickles. It is a major agricultural pest and a threat to native ecosystems.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Solanum douglasii is most commonly found west of the Rocky Mountains. It can be difficult to distinguish from S. nigrescens, but its longer, slightly tapered anthers on very short (relative to anther length) filaments is a good distinguishing character for plants in flower. The buds of S. douglasii are more pointed than those of S. nigrescens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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