Mexican Pricklypoppy

This yellow juice of the plant is medicinally used in dropsy, jaundice and cutaneous affection. The seeds are said to be poisonous and have narcotic properties and yields a fixed oil which has been in use amongst West Indian practitioners as an aperient. It exercises a soothing influence when applied externally in headache and also in herpetic and other forms of skin disease. A pale yellow clear limpid oil, obtained from the seeds, is used in lamps and medicinally in ulcers and erudtions.

Argemone mexicana is probably native to southern Florida as well as the Caribbean islands and has been introduced along the coast of the United States from New England to Texas and, more infrequently, inland. Although it has been reported from Mississippi, no specimens are known. It is widespread in temperate and tropical regions around the world by introduction.

A Prickly glabrous annual herb, 30-125 cm tall, branched. Leaves alternate, elliptic-oblong, pinnatifid, semiamplexicaul, sinuate-lobulated; variegated green and white, 5-20 cm long, 2-8 cm broad, ultimate segments, dentate, prickly on the margin, midrib and the veins beneath; Flowers sessile, 3-8 cm in diam., subtended by 2-3 foliaceous bracts. Sepals 8-12 mm long, 5-7 mm broad, with an acute, terete horn below the apex, very sparsely prickly outside, concave, imbricate caducous. Petals 4-6, obovate, 2.5-3.5 cm long, (1.5-)2-2.5 cm broad, narrowed below, bright yellow, imbricate, more or less crumpled in bud. Stamens indefinite, 8-12 mm long; anther c. 2 mm long, curved after flowering. Ovary ovate, 8-10 mm long, 3-5 mm broad covered with long soft spines; stigma red, 3-6 lobed; lobes usually broad. Capsule, oblong or elliptic-oblong, 2.5-4 cm long, 1.2-2 cm broad, with rounded ribs, covered with sharp erect prickles; valves 3-6. Seeds many, blackish brown to brown, ± rounded, 1.5-2 mm in diam, with fine, con¬spicuous tuberculae.

Plants annual. Stems often branching from base, 2.5-8 dm, unarmed or sparingly prickly. Leaf blades: surfaces unarmed or sparingly prickly on veins; proximal lobed 1/2 or more distance to midrib; distal more shallowly lobed, mostly clasping. Inflorescences: buds subglobose, body 10-15 × 9-13 mm, unarmed or sparingly prickly; sepal horns terete, 5-10 mm, unarmed. Flowers 4-7 cm broad, subtended by 1-2 foliaceous bracts; petals bright yellow or rarely pale lemon yellow; stamens 30-50; filaments yellow; pistil 4-6-carpellate. Capsules oblong to broadly ellipsoid, 25-45 × 12-20 mm (including stigma and excluding prickles when present), unarmed or prickly, longest prickles 6-10 mm. Seeds 1.6-2 mm. 2 n = 28.

Tropical America. A pantropical weed.

Distribution: Native of West Indies and Mexoico, but naturalized in most of the warm countries of the world as a weed.

Ont.; Ala., Conn., Fla., Ga., Ill., Ind., Kans., La., Md., Mass, Mich., Mo., Nebr., N.J., N.Y., N.C., Pa., S.C., Tenn., Tex., Va.; Mexico; West Indies; Central America.

150-1400 m

Fl.Per. February-May.

Flowering and fruiting spring-fall, or throughout year in tropics.

Waste places, often a weed of roadsides, dooryards, fallow fields; 0-1500m.

Argemone leiocarpa Greene - F W2