Including Fumariaceae of Michigan Flora.
The Fumariaceae are sometimes recognized as a separate family, differing in bilateral symmetry of the flowers and watery sap. All of our representatives of Papaveraceae in the strict sense have a colored (yellow to red-orange or milky) sap.
1. Flowers apetalous (and the sepals early deciduous), in a large, branched, many-flowered panicle-like inflorescence.
1. Flowers with showy petals, solitary or in a few-flowered inflorescence.
2. Corolla bilaterally symmetrical; sap watery, clear.
3. Flowers with the 2 outer petals identical, thus with 2 obscure to strong lobes or spurs at base, slightly compressed at right angles to the plane of symmetry; leaves basal or, if cauline, plant a vine climbing by the petioles.
4. Plant a delicate vine; leaves all cauline; corolla white to pale pink; persistent until fall.
4. Plant an erect perennial; leaves basal (except in Lamprocapnos); corollas white, pink, or purple, deciduous in the spring.
5. Leaves all basal, flowering stem leafless.
5. Leaves borne on the flowering stem.
3. Flowers with only 1 petal spurred, slightly compressed parallel to the plane of symmetry; leaves cauline (as well as sometimes basal) and plant not a vine.
6. Ovary and fruit nearly spherical; fruit indehiscent, 1-seeded; corolla purplish, the tip deep red.
6. Ovary and fruit linear; fruit dehiscent from the base upward (as in a silique), several-seeded; corolla yellow, pink with a yellow-tip or uniformly purplish.
7. Flowers pink, yellow-tipped; seeds ca. 1–1.5 mm wide; plants ± erect, the terminal inflorescences definitely surpassing the leaves.
7. Flowers yellow or purple; seeds ca. 1.8–2.2 mm wide; plants ± spreading or sprawling, the terminal inflorescences barely if at all surpassing the leaves (except in the rare perennial introduction, C. solida with a round tuber).
2. Corolla regular, sap colored whitish to yellow or red-orange.
8. Leaves ternately dissected into numerous very narrowly linear lobes, glabrous to puberulent.
8. Leaves simple to pinnatisect, but segments (if any) broader and often bristly (or even spiny).
9. Petals (7–) 8 (rarely more), over twice as long as wide, not wrinkled or crumpled in the bud; leaves basal (flowers scapose), palmately veined and lobed.
9. Petals 4 (more if flower “double”), less than twice as long as wide, wrinkled or crumpled in the bud; leaves cauline as well as basal, pinnately veined and usually lobed.
10. Leaves with distinct stiff sharp spines on teeth and lobes; spines also on buds, fruit, and (sparsely) stem.
10. Leaves without spines (or only obscure, weak ones in Papaver); spines absent on fruit.
11. Petals white, pink, red, or purple; fruit opening by a ring of pores or chinks beneath the stigmatic disc; sap milky white.
11. Petals yellow; fruit dehiscent to the base; sap yellow-orange.
12. Pistil with a definite style persisting and elongating (to ca. 8 mm) on the fruit; ovary and fruit long-pubescent, ellipsoid, splitting from apex to base; cauline leaves 2 (–3), opposite.
12. Pistil with little or no definite style (less than 2 mm); ovary and fruit linear, splitting from base to apex (as in a silique), glabrous or at most (Glaucium) very scabrous or tuberculate; cauline leaves several, alternate.
13. Distal leaves sessile (not clasping) or petiolate; fruit ca. 3–5 cm long; petals not over 1.5 cm long.
13. Distal leaves cordate-clasping; fruit becoming over 10 cm long; petals at least 3 cm long.