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cut-leaf nightshade, three flower nightshade

melon-leaf nightshade, watermelon nightshade

Habit Herbs, annual, decumbent to prostrate, unarmed, to 0.4 m, fleshy, nearly glabrous to moderately pubescent, hairs unbranched, to 2 mm, eglandular, rarely glandular. Herbs, annual, spreading, sparsely to moderately armed, 0.3–0.8 m, prickles yellowish, straight, needlelike, 3–7 mm, sparsely to densely pubescent, hairs short, unbranched, glandular, occasionally with a few longer, unbranched, eglandular hairs, abaxial leaf surfaces usually also with sessile to short-stalked, few-rayed, stellate hairs, central ray equal to or longer than lateral rays.
Leaves

petiolate;

petiole 0.5–2.5 cm;

blade simple, elliptic to oblong, 2–5 × 1–3 cm, margins shallowly lobed to deeply and regularly pinnatifid with 3–6 lobes per side, lobe margins entire or occasionally coarsely lobed, base cuneate and decurrent.

petiolate;

petiole 2–7 cm;

blade simple to compound, broadly ovate, 4–10(–15) × 3–8 cm, margins bipinnately lobed or divided with 3–4 main leaflets per side, these with obtuse or rounded lobes, base truncate.

Inflorescences

extra-axillary, unbranched, umbel-like, 1–6-flowered, 1–3 cm.

extra-axillary, unbranched, 4–10-flowered, 3–11 cm.

Pedicels

spreading and 0.5–1.5 cm in flower, reflexed and 0.5–1.5 cm in fruit.

1–2 cm in flower, 1–2 cm and erect in fruit.

Flowers

radially symmetric;

calyx accrescent and covering base of berry, unarmed, 2–4(–7) mm, moderately pubescent, lobes deltate, reflexed;

corolla white or light purple with green or purplish central star, stellate, 0.5–1 cm diam., with sparse interpetalar tissue;

stamens equal;

anthers narrowly ellipsoidal, 2.5–4 mm, dehiscent by terminal pores that open into longitudinal slits;

ovary glabrous.

bilaterally symmetric;

calyx accrescent and tightly covering fruit, densely prickly, 2.5–3.8 mm, densely glandular-pubescent, lobes linear-lanceolate;

corolla violet or blue, pentagonal-stellate, 2.5–3.5 cm diam., with interpetalar tissue at margins and bases of lobes;

stamens unequal, lowermost much longer and curved;

anthers narrow and tapered, dehiscent by terminal pores, short anthers yellow, 6–10 mm, longer anther purplish, 11–16 mm;

ovary glabrous.

Berries

shiny dark green to purplish black, globose, 0.8–2 cm diam., glabrous, with 13–30 sclerotic granules.

brown, globose, 0.8–1.2 cm diam., glabrous, dry, without sclerotic granules.

Seeds

yellow, plump, 2–3 × 2–2.5 mm, minutely pitted.

dark brown, flattened, 2.3–3 × 2–2.5 mm, reticulately wrinkled, ridged, or undulate.

2n

= 24.

= 24.

Solanum triflorum

Solanum citrullifolium

Phenology Flowering Apr–Sep.
Habitat Disturbed areas, roadsides, stream banks, along railroad tracks, prairie dog towns.
Elevation (0–)700–2900 m. ((0–)2300–9500 ft.)
Distribution
from FNA
AZ; CA; CO; IA; ID; KS; MA; MI; MN; MO; MT; ND; NE; NM; NV; OK; OR; SD; TX; UT; WA; WY; AB; BC; MB; SK; South America (Argentina) [Introduced in Europe, Africa, Australia]
[WildflowerSearch map]
[BONAP county map]
from USDA
sc United States; se United States; Mexico
[BONAP county map]
Discussion

Solanum triflorum is found in South America (Argentina) and is also considered to be native to central and western North America. It is occasionally adventive in the eastern United States. It is poisonous to livestock and can become a serious weed in cultivated fields, especially in the Great Plains.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

North American plants identified as Solanum heterodoxum Dunal are largely misidentifications of S. citrullifolium. Solanum heterodoxum in the current sense is now restricted to Mexico.

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Stems scattered-prickly with fewer than 20 prickles per cm of stem; prickles often to 1 mm diam. at base; stems densely glandular-pubescent.
var. citrullifolium
1. Stems densely bristly with 25+ bristles per cm of stem; bristles mostly less than 0.5 mm diam. at base; stems sparsely glandular-pubescent.
var. setigerum
Source FNA vol. 14. FNA vol. 14.
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. 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. triquetrum, S. umbelliferum, S. viarum, S. wallacei
S. americanum, S. aviculare, S. bahamense, S. campechiense, S. capsicoides, S. carolinense, S. chenopodioides, 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
Subordinate taxa
S. citrullifolium var. citrullifolium, S. citrullifolium var. setigerum
Name authority Nuttall: Gen. N. Amer. Pl. 1: 128. (1818) A. Braun: Index Seminum (Friburg) 1849: [3]. (1849)
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