The familiar cultivated herbaceous Peonies (Paeonia, in the family Paeoniaceae) may persist indefinitely on abandoned homesites, and appear where garden refuse is dumped, but are scarcely established. Plants have been collected in Crawford and Lenawee Cos. They would key to Ranunculaceae in Key J of the family keys, but are readily distinguished by their unique, large flowers, distinctive habit with stout stems in large clumps, and few leathery, alternate compound leaves. Though many species are grown, the commonest cultivated plants are derived from Paeonia lactiflora Pall. and P. officinalis L.
1. Plant a vine (twining, if at all, by petioles); leaves opposite; fruit with a conspicuous persistent feathery style.
1. Plant an erect or stemless herb; leaves alternate or basal (sometimes with a single whorl of “involucral” cauline leaves); fruit without a plumose style.
2. Perianth with 1 or more distinct spurs or hoods.
3. Flower regular, red and yellow or purple, white, or pink, with all petals spurred; fruit a group of follicles (normally 5).
3. Flowers bilaterally symmetrical, blue, with 1 long sepal spur enclosing 1 or 2 petal spurs or the upper petaloid sepal formed into a conspicuous hood; fruit 1 or 3 follicles.
4. Follicles solitary; plants annual; leaves divided into narrowly linear segments.
4. Follicles 3; plants perennial; leaves with broader segments or merely lobed.
5. Upper petaloid sepal formed into a conspicuous hood.
5. Upper petaloid sepal spurred.
2. Perianth without spurs.
6. Flowers numerous per inflorescence (6 to many in a raceme or panicle), the perianth much less conspicuous than the stamens (or carpels), which offer the most showy portion of each flower; leaves clearly compound.
7. Inflorescence open, panicle-like; teeth or lobes of leaflets few, ± rounded or obtuse (occasionally acute); fruit an achene.
Thalictrum (in part)
7. Inflorescence a raceme; teeth or lobes of leaflets numerous, acute; fruit a follicle or fleshy berry.
6. Flowers solitary or few (not over 6) per inflorescence (though a plant may bear more than 1 inflorescence), the perianth more conspicuous than the stamens (except in one species with solitary flower and simple leaves, Hydrastis canadensis); leaves simple or compound.
9. Flowers solitary, on a leafy stem or a scape; leaves simple, (sometimes ± lobed or cleft) or strictly once-compound.
10. Leaves linear, entire; flowers with a greatly elongated receptacle (often more than 10 times as long as wide); tap-rooted annual.
10. Leaves broad, lobed, toothed, or trifoliolate; receptacle spherical or only slightly elongated; fibrous-rooted or tuberous perennials.
11. Plant without a leafy stem, the flowers scapose (peduncles and leaves all basal); perianth white, pink, or blue (not yellow or yellowish).
12. Leaves trifoliolate, toothed; fruit a follicle (ca. 3–7 per flower) on a distinct stalk; flowers white; plants essentially glabrous.
12. Leaves simple, 3 (–5)-lobed, entire; fruit an achene (numerous per flower), sessile; flowers white, pink, or blue; plants with peduncles and new foliage long-pilose.
11. Plant with an erect, reclining, or stoloniferous leafy or leafy-bracted stem; perianth (or at least the petals) yellow, white, cream, or greenish white.
13. Perianth early deciduous (as the flower opens), the stamens comprising the conspicuous aspect to the flower; fruit a red berry.
13. Perianth persistent, more conspicuous than the stamens; fruit an achene or follicle.
14. Flowers sessile, blooming in very early spring (March and April), closely subtended by a whorl of 3 sessile involucral bracts; fruits follicles.
14. Flowers peduncled, blooming in spring or summer, subtended by petioled bracts, alternate bracts, or bractless; fruits achenes.
15. Flowers with petaloid sepals and no petals; cauline leaves (or bracts) opposite or whorled.
Anemone (in part)
15. Flowers appearing to have both petals and sepals; cauline leaves or bracts absent or alternate.
16. Leaves all unlobed, entire or at most denticulate or crenate.
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16. Leaves (at least the cauline ones) with blades deeply cleft or lobed more than halfway to the base.
17. Flowers solitary on long slender peduncles from the nodes; sepals 3.
17. Flowers usually at least 2 in a branched inflorescence; sepals 5.
Ranunculus (in part)
9. Flowers more than 1 on a leafy stem (never on a scape) [if flower solitary on small plants, the leaves dissected or at least twice-compound]; leaves simple or compound.
18. Perianth with both sepals and petals.
19. Leaves all unlobed (except sometimes at cordate base), entire or at most denticulate or crenate.
20. Leaf blades denticulate or entire, linear to lance-elliptic, tapering into the shorter petiole (or often indistinguishable from it); achenes smooth or finely reticulate, glabrous.
Ranunculus (in part)
20. Leaf blades crenate to entire, obovate to reniform, truncate to cordate at the base, mostly much shorter than the distinct petioles; achenes smooth and pubescent or longitudinally ridged.
21. Petals ca. 8–10 (–14) mm long; sepals 3 (–4); achenes pubescent, at least 2 mm long, not ridged; roots strongly tuberous-thickened.
21. Petals ca. 2.5–4 (–5) mm long; sepals 5; achenes glabrous, less than 2 mm long (including beak), longitudinally ridged; roots not tuberous.
19. Leaves (at least the cauline ones) with blades deeply cleft or lobed more than halfway to the base.
Ranunculus (in part)
18. Perianth of ± petaloid sepals and no petals (or these modified to staminodia or nectaries).
22. Leaves simple, toothed to almost entire but not cleft or lobed (except at cordate base of blade); perianth bright yellow.
22. Leaves deeply cleft, dissected, or compound; perianth not yellow (white, bluish, cream, or maroon).
23. Leaves pinnately dissected (including a conspicuous involucre beneath each flower), the segments less than 1.5 mm wide, glabrous; ovaries united; rarely escaped from cultivation.
23. Leaves compound or palmately lobed, the leaflets or lobes at least 1.5 mm wide, pubescent or glabrous; ovaries separate; mostly native.
24. Principal leaves (at least the basal ones) clearly twice-compound, with broad leaflets on slender petiolules; teeth or lobes of leaves broadly rounded; perianth white (rarely pinkish); foliage and fruit glabrous.
25. Leaves all basal, plus an involucral whorl beneath the umbellate flowers; carpels essentially without styles, ripening into achenes.
25. Leaves alternate and basal, the flowers terminal and often axillary; carpels with prolonged styles, ripening into beaked follicles.
24. Principal leaves palmately lobed, cleft, or barely once-compound (leaflets scarcely petioluled); teeth or lobes of leaves sharply acute; perianth white, cream, greenish, or maroon; foliage (including stems and petioles) and fruit ± pubescent (glabrous in Helleborus).
26. Cauline leaves alternate; flowers white to pinkish or ± green, ca. 4 cm or more in diameter; fruit a follicle; rarely escaped from cultivation, blooming in earliest spring or late winter (often in snow).
26. Cauline leaves or bracts opposite or whorled; flowers white, cream, or maroon, usually smaller; fruit an achene; native, blooming spring-summer.
Anemone (in part)