Herbs, annual or occasionally short-lived perennial, 30-100 cm tall, usually stout. Stems mostly short, branched, with sparse explanate fulvous spines. Basal leaves dense; petiole 5-10 mm; blade glaucous with blue-green markings on veins, paler abaxially, broadly oblanceolate or obovate to elliptic, 5-20(-25) × 2.5-7.5(-8) cm, glabrous, sparsely sharply spiny on veins, base cuneate, margin pinnatipartite, apex acute; lobes undulate teeth, teeth apically spiny. Cauline leaves alternate, similar to basal leaves, but upper leaves smaller and sessile, often subamplexicaul. Flowers solitary, sometimes in few-flowered cymes. Pedicel very short. Flower buds ovoid, ca. 1.5 cm. Sepals 2(or 3), cymbiform, ca. 1 cm, apex spurred, glabrous or sparsely spiny. Petals 6, yellow or orange, broadly obovate, 1.7-3 cm, base broadly cuneate, apex rounded. Filaments ca. 7 mm; anthers narrowly oblong, 1.5-2 mm, coiling after dehiscence. Ovary elliptic or oblong, 7-10 mm, with explanate fulvous spines; styles very short; stigmas dark red, 4-6-lobed. Capsule oblong to broadly elliptic, 2.5-5 × 1.5-3 cm, sparsely fulvous spiny, 4-6-valved dehiscing from apex to 1/4-1/3 of length. Seeds spherical, 1.5-2 mm in diam., obviously tessellate. Fl. and fr. Mar-Oct. 2n = 28.
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.
Argemone mexicana L., Sp. Pl. 508. 1753.
Hierbas espinosas, hasta 80 cm de alto, glabras y glaucas, látex amarillo. Hojas hasta 20 cm de largo y 8 cm de ancho, pinnatífidas con espinas terminales en cada lobo, sésiles. Flores grandes, solitarias y terminales, abrazadas por una bráctea foliosa; sépalos 3, ca 15 mm de largo, caducos; pétalos 6, ca 20 mm de largo, amarillos; estambres numerosos; estilo corto, estigma grueso. Cápsula elipsoidal, 23.5 cm de largo, aculeada, 46-valvada; semillas numerosas, globosas, 2 mm de diámetro, conspicuamente foveoladas.
Común en áreas perturbadas en todas las zonas del país; 01250 m; fl y fr todo el año; Neill 4626, Stevens 5737; desde el sur de los Estados Unidos hasta Argentina, también en las Antillas, naturalizada en el Viejo Mundo. Género de ca 28 especies del Nuevo Mundo. "Cardosanto".
Coarse, prickly annual of sunny habitats, seldom as much as 1 m. tall; stems fleshy, lightly setose-spinose, containing a yellow sap; leaves moderate, sessile, the blade mostly obovate in outline, 5-25 cm. long and up to 8 or 9 cm. wide, the upper leaves smaller, irregularly lobed or incised, the lobes spinose-dentate and rigidly mucronate at the apex, glabrous, glaucous, pinnate-veined, the lateral veins few, obscurely and laxly reticulate; inflorescence as described for the genus; sub- tending bracts consisting of 2-3 very reduced leaves from condensed nodes; flowers showy, light or dark yellow; sepals 3, roughly ovate, about 2 cm. long, rigidly mucronate-spinose apically, usually bearing a few smaller spines below, glabrous and glaucous; petals normally 6, broadly obovate, mostly 2-4 cm. long, glabrous, more or less parallel-veined. Capsule usually oblongoid, 4- to 6-valvate, prominently spinose; seeds many, from 4-6 parietal placentae, globose, reticulate, glabrous.
"Annual, mostly 2.5–8 dm; lvs usually blotched with paler green; fls closely subtended by the upper lvs; pet yellow or cream, 1.5–3.5 cm; stamens 30–50; 2n=28. Native of tropical Amer., occasionally escaped from cult. as far n. as Mass. May–Sept."
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.
Capsule smooth or setose, 3–4 cm. long
Leaves semi-amplexicaul, pinnately lobed
Leaves sessile, ± amplexicaul, sinuate-pinnatifid with prickly teeth, often variegated.
Erect, glaucous herb up to 1 m. tall.
Flowers 3.5–4.5 cm. in diam., bright yellow, cream or white.
Seeds up to 2 mm. in diameter, subspherical with a small beak at one end ; testa pitted in rows radiating from the micropyle end.
Capsule oblong to broadly ellipsoid, 1.2–4.5 × 2.5 × 2.0 cm. ; valves 4–6, which split away from the vascular strands for about 1/3 of their length, exposing a cage-like frame of these vascular strands, attached apically to the persistent stigma ; outer valve-surface prickly in all tropical East African specimens seen (see Note below).
Stigma and style persistent, 1–3 mm. long in fruit.
Petals 6, yellow more rarely cream-white, glabrous.
Sepals 3, caducous, covered to a greater or lesser degree with prickles.
Flowers 2.5–4.5 cm. in diameter, subtended by 1 or 2 foliaceous bracts.
Leaves sessile, ± sheathing (amplexicaul); prickles if present mainly on the veins of the abaxial surface ; leaves with midrib and veins irregularly outlined in greyish-white on the adaxial surface.
Herbs erect up to about 1.2 m. high, often branching near the base.
Argemone mexicana grows as an herbaceous annual-biennial to less than 1 m in height. The entire plant is covered with stiff sharp prickles. The leaves are arranged alternately, are sessile on the stems, and up to 20 cm in length. The leaf is sinuate and lobed, with a spiny margin, and has whitish venation. The vegetative parts produce a yellowish sap. The complete, perfect, actinomorphic flowers are arranged solitarily and subtended by bracts. The calyx has 3 greenish sepals each tipped with a spine. There are 6 bright yellow petals in the corolla. There are numerous stamens and a superior ovary with a single locule. The fruit is a poricidal capsule that is covered with spines.
Argemone mexicana grows in Human Altered environments (abandoned fields, yards, and roadsides).
Southern United States and Mexico to Argentina and Chile; West Indies. Naturalized into Old World.
Argemone mexicana occurs throughout all the island groups of the Lucayan Archipelago as well as the southern United States, the entire Caribbean region, and Central and South America. It is also known to occur in Bermuda as well as becoming naturalized as a weedy species throughout the Africa and Asia
Argemone mexicana has been used in the Bahamas to treat a wide variety of diseases including respiratory problems (asthma, coughing, hiccups) as well as blood related diseases (hepatitis, jaundice, and high blood pressure), ringworm, and to remove warts. Oils can be extracted from the seeds and roots and have been used for lighting. Extracts can also be used as a pesticide. In general extracts from Argemone mexicana are considered poisonous and care should be taken when ingesting it.