1. Argemone L. (prickly poppy)
(Ownbey, 1958)
Plants annual or
biennial (perennial herbs elsewhere), with taproots; sap yellow (white to
orange elsewhere). Aerial stems strongly ascending, usually sparsely to moderately
prickly, also somewhat glaucous. Leaves basal and alternate on the stems, the
stem leaves progressively shorter toward the stem or branch tips, all sessile,
at least the uppermost leaves usually with a pair of rounded auricles at the
base, clasping the stem. Leaf blades moderately to deeply pinnately lobed with
relatively broad, often U-shaped sinuses, the lobes variously shaped, with
irregularly toothed margins, these armed with staw-colored, slender prickles,
the surfaces glabrous or armed with scattered slender prickles along the main
veins, glaucous, often with lighter mottling along the main veins. Flowers
terminal, loose clusters (sometimes appearing as small panicles) at the stem or
branch tips, sometimes reduced to a solitary flower, the flowers short- to
long-stalked, the stalk erect or ascending at flowering, mostly subtended by 1
or 2 bracts, these similar in appearance to leaves but smaller, the receptacle
slightly expanded at the tip but not forming a cup or disc. Sepals 3, free,
shed individually as the flower opens, the body 9–18 mm long, oblong elliptic,
broadly pointed at the tip, sometimes armed with prickles, also with a
prominent, ascending, conic, dorsal horn near the tip. Petals 4, broadly
obovate, broadly rounded and often somewhat uneven or slightly ruffled at the
tip, white to pale yellow or yellow. Stamens numerous. Ovary lacking a
well-differentiated style at flowering, the stigma more or less capitate, with
4–6, shallow, spreading lobes. Fruits erect or ascending, oblong-elliptic to
elliptic, variously nearly truncate to angled to a sharply pointed tip, the
surface usually with numerous stout, ascending prickles, these often attached
to shallow nipplelike structures, also longitudinally 4–6-ribbed, dehiscing to
about 1/3 of the way from the tip by valves, leaving the persistent stigma
attached to a network of vascular tissue exposed around the seeds. Seeds
1.5–2.0 mm long, more or less globose but abruptly tapered to a small point at
the base, the short aril inconspicuous, the surface with a prominent network of
ridges and pits, brown to reddish brown, not shiny. Thirty-two species, North
America, South America, Hawaii; introduced in the Old World.