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horse nettle, silver-leaf nightshade, white horse-nettle

American black nightshade, American black or common or West Indian nightshade, glossy nightshade, little white nightshade, small-flower nightshade, white nightshade

Habit Herbs or shrubs, perennial, erect, rhizomatous, sparsely to densely armed, to 1 m, prickles orange to brown, straight, to 5 mm, densely silvery-pubescent, hairs sessile or subsessile, stellate, scalelike, 10–15-rayed, central ray shorter than lateral rays, lateral rays fused at center. Herbs to subshrubs, annual to perennial, erect, unarmed, to 1.5 m, glabrate to moderately pubescent, hairs whitish, unbranched, to 1 mm, eglandular.
Leaves

petiolate;

petiole 1–5 cm;

blade simple, lanceolate to oblong, 5–15 × 0.5–3 cm, margins undulate, subentire to sinuate or shallowly lobed, lobe margins entire, base truncate to cuneate.

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.

Inflorescences

extra-axillary, unbranched, 3–5(–7)-flowered, 3–5 cm.

extra-axillary or leaf-opposed, unbranched, usually umbel-like, 3–10-flowered, 0.5–3 cm.

Pedicels

1–3 cm in flower, reflexed and 1–3 cm in fruit.

erect or spreading, 0.3–1 cm in flower, to 1.5 cm in fruit.

Flowers

radially symmetric;

calyx not accrescent, unarmed or with sparse prickles, 5–10 mm, densely silvery-stellate-pubescent, lobes linear-lanceolate;

corolla pale to deep blue or violet, rarely white, pentagonal-stellate, 2–3(–3.5) cm diam., with abundant interpetalar tissue;

stamens equal;

anthers narrow and tapered, 6–9 mm, dehiscent by terminal pores;

ovary glabrous to densely stellate-pubescent.

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.

Berries

yellow to orange, drying brown or black, globose, 0.5–1.5 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.

Seeds

yellowish, flattened, 3–5 × 2–4 mm, minutely pitted.

pale yellow to brown, 1–1.5 × 0.5–1.5 mm, minutely pitted.

2n

= 24, 48, 72.

= 24.

Solanum elaeagnifolium

Solanum americanum

Phenology Flowering Mar–Nov. Flowering May–Nov (year-round in Fla.).
Habitat Dry sites, open woods, dis­turbed areas, roadsides, railroads, fields. Weedy habitats, secondary forest, disturbed areas.
Elevation 0–2100 m. [0–6900 ft.] 0–1000(–2000) m. [0–3300(–6600) ft.]
Distribution
from FNA
AL; AR; AZ; CA; CO; FL; GA; ID; IL; IN; KS; KY; LA; MD; MO; MS; NC; NE; NM; NV; OK; OR; SC; TN; TX; UT; WA; Mexico; West Indies; South America (Argentina, Chile, Paraguay, Uruguay) [Introduced elsewhere in South America (Colombia, Peru), Eurasia (Mediterranean, Middle East, India, Pakistan), Africa, Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AZ; CA; FL; GA; LA; MO; MS; OR; SC; TX; UT; WA; BC; Mexico; Central America; South America; West Indies [Introduced in Europe, Asia, Africa, Pacific Islands, Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Solanum elaeagnifolium has a disjunct native distribution. It occurs in arid regions of the southwestern United States and Mexico and also in Argentina, Chile, Paraguay, and Uruguay. North American plants are diploid, whereas those in Argentina are diploid, tetraploid, or hexaploid. It is invasive and considered a noxious weed in 21 states in the flora area as well as in many tropical and subtropical regions worldwide. It is toxic to livestock and can form large, rhizomatous patches that are difficult to eradicate.

A white-flowered form has been recognized as Solanum elaeagnifolium forma albiflorum Cockerell.

(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.)

Source FNA vol. 14. Treatment authors: Lynn Bohs1, 1The author wishes to acknowledge co-authorship with David M. Spooner† on S. jamesii and S. stoloniferum and with Sandra Knapp and Tiina Särkinen on the black nightshade species.. FNA vol. 14. Treatment authors: Lynn Bohs1, 1The author wishes to acknowledge co-authorship with David M. Spooner† on S. jamesii and S. stoloniferum and with Sandra Knapp and Tiina Särkinen on the black nightshade species..
Parent taxa Solanaceae > Solanum Solanaceae > Solanum
Sibling taxa
S. americanum, S. aviculare, S. bahamense, S. campechiense, S. capsicoides, S. carolinense, S. chenopodioides, S. citrullifolium, S. cordicitum, S. davisense, S. deflexum, S. dimidiatum, S. diphyllum, S. donianum, S. douglasii, S. dulcamara, S. emulans, S. erianthum, S. furcatum, S. hindsianum, S. interius, S. jamaicense, S. jamesii, S. laciniatum, S. lanceolatum, S. lumholtzianum, S. lycopersicum, S. marginatum, S. mauritianum, S. nigrescens, S. nigrum, S. nitidibaccatum, S. novomexicanum, S. perplexum, S. pseudocapsicum, S. pseudogracile, S. pumilum, S. rostratum, S. sarrachoides, S. seaforthianum, S. setigeroides, S. sisymbriifolium, S. stoloniferum, S. tampicense, S. tenuipes, S. torvum, S. triflorum, S. triquetrum, S. umbelliferum, S. viarum, S. wallacei
S. aviculare, S. bahamense, S. campechiense, S. capsicoides, S. carolinense, S. chenopodioides, S. citrullifolium, S. cordicitum, S. davisense, S. deflexum, S. dimidiatum, S. diphyllum, S. donianum, S. douglasii, S. dulcamara, S. elaeagnifolium, S. emulans, S. erianthum, S. furcatum, S. hindsianum, S. interius, S. jamaicense, S. jamesii, S. laciniatum, S. lanceolatum, S. lumholtzianum, S. lycopersicum, S. marginatum, S. mauritianum, S. nigrescens, S. nigrum, S. nitidibaccatum, S. novomexicanum, S. perplexum, S. pseudocapsicum, S. pseudogracile, S. pumilum, S. rostratum, S. sarrachoides, S. seaforthianum, S. setigeroides, S. sisymbriifolium, S. stoloniferum, S. tampicense, S. tenuipes, S. torvum, S. triflorum, S. triquetrum, S. umbelliferum, S. viarum, S. wallacei
Synonyms S. nigrum var. americanum, S. nigrum var. nodiflorum, S. nodiflorum, S. ptychanthum
Name authority Cavanilles: Icon. 3: 22, plate 243. (1795) Miller: Gard. Dict. ed. 8 Solanum no. 5. (1768)
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