Solanum viarum
Solanum americanum
tropical soda apple
American black nightshade, American black or common or West Indian nightshade, glossy nightshade, little white nightshade, small-flower nightshade, white 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 1–4 cm;
blade simple, ovate to ovate-elliptic, 2–10.5 × 1–4.5 cm, margins entire or shallowly sinuate-dentate, base decurrent.
extra-axillary, sessile or nearly so, unbranched, 3–5-flowered.
extra-axillary or leaf-opposed, unbranched, usually umbel-like, 3–10-flowered, 0.5–3 cm.
0.7–1.1 cm in flower, 1–2 cm in fruit.
erect or spreading, 0.3–1 cm in flower, to 1.5 cm 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 somewhat accrescent, unarmed, 1–3 mm, lobes deltate, strongly reflexed in fruit;
corolla white, sometimes with yellowish central star, stellate, 0.4–0.8 cm diam., without interpetalar tissue;
stamens equal;
anthers ellipsoidal, 0.7–1.5 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.
shiny purplish black, globose, 0.5–1 cm diam., glabrous, with (0–)2–4(–6) sclerotic granules, usually 2–4 larger and 2 smaller.
reddish brown, flattened, 2–3 × 2–2.5 mm, minutely pitted.
pale yellow to brown, 1–1.5 × 0.5–1.5 mm, minutely pitted.
= 24.
= 24.
Solanum viarum
Solanum americanum
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 americanum is a morphologically variable and globally distributed weedy species. It has often been confused with other species in the black nightshade group such as S. emulans, S. nigrescens, S. nigrum, and S. pseudogracile and has often been referred to as S. nodiflorum in floristic treatments. It is distinguished by its very short anthers and shiny black mature fruits with strongly reflexed calyx lobes and usually two to four (rarely none or as many as six) sclerotic granules per fruit. Leaf shape and pubescence can vary considerably throughout its range, and there are some suspected cases of introgression with other species such as S. nigrescens or S. pseudogracile. The name S. nigrum has been misapplied to S. americanum (for example, A. E. Radford et al. 1968).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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