6b. Leaf-segments ovate to lanceolate =Golden Alexander, Taenidia integerrima.=
7a. Leaves pinnately compound; some of the leaflets incised or pinnatifid --8.
7b. Leaves ternately compound; the segments crenate or serrate --9.
7c. Leaves deeply palmately cleft or divided; flowers in head-like umbels --18a.
8a. Leaf-segments obtuse, rounded, or cordate at the base (6-15 dm.
high; summer) =Wild Parsnip, Pastinaca sativa.=
8b. Leaf-segments narrowed to the base (4-8 dm. high; spring) =Prairie Parsley, Polytaenia nuttallii.=
9a. Terminal leaflets conspicuously stalked, their total length, including stalk, at least 50% greater than the length of the lateral leaflets (Meadow Parsnip) --10.
9b. Terminal leaflets not conspicuously stalked, their total length, including stalk, about equaling the lateral leaflets (4-8 dm. high; late spring) (Golden Alexander) --12.
10a. Flowers purple (4-8 dm. high; early summer) =Meadow Parsnip, Thaspium aureum var. atropurpureum.=
10b. Flowers yellow --11.
11a. Stem-leaves once-ternate; leaflets finely serrate (4-8 dm. high; early summer) =Meadow Parsnip, Thaspium aureum.=
11b. Many stem-leaves 2-3-ternate; leaflets coa.r.s.ely serrate or incised (6-12 dm. high; early summer) =Meadow Parsnip, Thaspium barbinode.=
12a. Basal and lower stem-leaves 2-3-ternate =Golden Alexander, Zizia aurea.=
12b. Basal leaves simple; stem-leaves once-ternate =Golden Alexander, Zizia cordata.=
13a. Leaves once-pinnate (or the submerged leaves decompound, if present) (summer) --14.
13b. Leaves ternately, palmately, or 2-3-pinnately compound --16.
14a. Leaflets mostly ovate or ovate-lanceolate, some of them coa.r.s.ely incised (3-9 dm. high) =Water Parsnip, Berula erecta.=
14b. Leaflets linear to oblong, serrate to nearly entire, not incised (6-15 dm. high) --15.
15a. Leaflets entire, or with a few low remote teeth =Cowbane, Oxypolis rigidior.=
15b. Leaflets finely but sharply serrate =Water Parsnip, Sium cicutaefolium.=
16a. Leaves princ.i.p.ally basal, decompound; flowers in early spring (1-2 dm. high) =Harbinger of Spring, Erigenia bulbosa.=
16b. Leaves princ.i.p.ally on the stem --17.
17a. Leaves palmately or ternately once-compound --18.
17b. Leaves 2-3 times compound or decompound --24.
18a. Flowers short-pedicelled, crowded in head-like umbels, greenish; ovary bristly (4-9 dm. high; early summer) (Black Snakeroot) --19.
18b. Flowers in open umbels, white --22.
19a. Styles short, not projecting beyond the bristles of the mature fruit --20.
19b. Styles long, projecting beyond the bristles of the fruit, and recurved --21.
20a. Staminate flowers on pedicels 3-4 mm. long, equaling or barely exceeding the fruit =Black Snakeroot, Sanicula trifoliata.=
20b. Staminate flowers short-pedicelled, concealed among the fruits =Black Snakeroot, Sanicula canadensis.=
21a. Fruit short-stalked, 4 mm. long or less =Black Snakeroot, Sanicula gregaria.=
21b. Fruit sessile, 6-7 mm. long =Black Snakeroot, Sanicula marilandica.=
22a. Umbel unsymmetrical, its branches irregular in length; plant slender (3-8 dm. tall; early summer) =Honewort, Cryptotaenia canadensis.=
22b. Umbel symmetrical with regular branches; plants tall and stout --23.
23a. Stem and leaves very p.u.b.escent (10-25 dm. high; summer) =Cow Parsnip, Heracleum lanatum.=
23b. Stem and leaves glabrous or nearly so (5-15 dm. high; early summer) =Masterwort, Imperatoria ostruthium.=
24a. Ovary and fruit bristly (4-10 dm. high) --25.
24b. Ovary and fruit smooth or winged, never bristly --27.
25a. Umbels loose, open, few-flowered; woodland plants blooming in spring (Sweet Cicely) --26.
25b. Umbels densely flowered; weedy plants blooming from summer to fall =Wild Carrot, Daucus carota.=
26a. Stem villous-p.u.b.escent =Sweet Cicely, Osmorhiza claytoni.=
26b. Stem glabrous except at the joints =Sweet Cicely, Osmorhiza longistylis.=
27a. Leaflets merely serrate (flowers in summer) --28.
27b. Leaflets coa.r.s.ely incised, so that the leaf appears dissected --30.
28a. Umbel densely p.u.b.escent (8-15 dm. high) =Angelica, Angelica villosa.=
28b. Umbel smooth --29.
29a. Leaf-segments broadly ovate (8-15 dm. high) =Angelica, Angelica atropurpurea.=
29b. Leaf-segments lanceolate (8-15 dm. high) =Water Hemlock, Cicuta maculata.=
29c. Leaf-segments linear (4-10 dm. high) =Water Hemlock, Cicuta bulbifera.=
30a. Princ.i.p.al branches of the umbel 2-5; fruit linear-oblong; woodland plants blooming in spring (2-4 dm. high) =Chervil, Chaerophyllum proc.u.mbens.=