1	Plants of high altitudes, (3500–)4000–5000 m, short and squat 5–20(–40) cm; stems usually much reduced, often thickened, unbranched.		(2)
+	Plants from varying altitudes and habitats, usually much larger (0.3–2 m), smaller specimens slender-stemmed.		(10)
2 (1)	Bracteole apex acute, acuminate or obtuse.		(3)
+	Bracteole apex 1–2-pinnate/pinnatifid.		(5)
3 (2)	Fruit wings narrow, crisped; calyx teeth lanceolate; rays thickened, particularly at the distal ends; pedicels flattened and winged.		1 Pleurospermum nubigenum
+	Fruit wings narrow or broad, plane; calyx teeth triangular or obsolete; rays uniform thickness, pedicels terete.		(4)
4 (3)	Petals white; fruit thinly winged; calyx teeth triangular; vittae 3 per furrow.		2 Pleurospermum pulszkyi
+	Petals purple-red; fruit broadly winged; calyx teeth obsolete; vittae 2 per furrow.		3 Pleurospermum lindleyanum
5 (2)	Bracteole apex 2-pinnate/pinnatifid; ultimate leaf segments linear, 0.3–0.5 mm broad; pedicels flattened.		4 Pleurospermum heterosciadium
+	Bracteole apex 1-pinnate/pinnatifid; ultimate leaf segments lanceolate, 0.5–5 mm broad; pedicels terete.		(6)
6 (5)	Compact rosette, stemless; inflorescence densely capitate, subsessile; rays reduced, crowded; fruit wings broad and sinuate, not dentate.		5 Pleurospermum hedinii
+	Stems usually distinct; inflorescences not densely capitate, usually distinctly pedunculate; rays not reduced, lax; fruit ribs prominent or irregularly dentate or sinuate winged.		(7)
7 (6)	Umbels usually subsessile; rays very unequal; fruit tuberculate, wings irregularly dentate.		8 Pleurospermum astrantioideum
+	Umbels distinctly pedunculate; rays subequal; if fruit winged then not tuberculate.		(8)
8 (7)	Plants with strong unpleasant odor; rays 14–30; fruit wings irregularly dentate.		9 Pleurospermum foetens
+	Plant without unpleasant odor; rays 5–15(–20); fruit ribs prominent to narrowly winged, wing margin entire.		(9)
9 (8)	Leaves 1–2-pinnate, ultimate segments ovate or orbicular; fruit ribs all broadly winged.		6 Pleurospermum stellatum
+	Leaves 2–3-pinnate, ultimate segments linear-lanceolate; fruit ribs prominent or narrowly sinuate- winged.		7 Pleurospermum nanum
10 (1)	Large, often robust plants, (0.5–)0.8–2 m, rarely shorter.		(11)
+	Small, slender plants, 20–40(–50) cm rarely taller.		(23)
11 (10)	Leaflets of lower leaves broadly ovate, regularly serrate, base truncate or cordate.		(12)
+	Leaflets of lower leaves variously lobed and dissected, often pinnatifid, not broadly ovate, bases usually cuneate to decurrent.		(13)
12 (11)	Umbels 8–10 cm across; rays 15–20, 4–7 cm; fruit 8–10 × 4–6 mm.		10 Pleurospermum rivulorum
+	Umbels 2–4 cm across; rays 6–8(–15), 0.6–2 cm; fruit 7–8 × 3–4 mm.		11 Pleurospermum rotundatum
13 (11)	Plants usually very robust, thick-stemmed (except P. stylosum); umbels (7–)12–28 cm across; rays (15–)25–40.		(14)
+	Plants less robust, slender-stemmed; umbels 3–15 cm across; rays 7–28.		(16)
14 (13)	Rays 15–35; fruit 4–6 mm; ribs sinuate-winged (Xinjiang).		12 Pleurospermum stylosum
+	Rays 20–40(–60); fruit 6–10 mm; ribs cristate- or plane-winged.		(15)
15 (14)	Ultimate leaf segments pinnatifid, lobes linear; calyx teeth conspicuous, triangular-ovate; fruit wings thick, cristate (NW China).		13 Pleurospermum uralense
+	Ultimate leaf segments coarsely dentate, lobes ovate; calyx teeth obsolete; fruit wings thin, broad and plane (SW China).		14 Pleurospermum aromaticum
16 (13)	Petioles of upper leaves expanded into auriculate sheaths; fruit oblong, 8–15 mm.		(17)
+	Petioles of upper leaves expanded or not, but not auriculate; fruit ovate to oblong-ovate, 3.5–8(–10) mm.		(18)
17 (16)	Leaves irregularly serrate; bracteoles ca. 5 mm broad; seed face deeply concave.		15 Pleurospermum angelicoides
+	Leaves regularly crenate; bracteoles ca. 1 mm broad; seed face slightly concave.		16 Pleurospermum longicarpum
18 (16)	Leaves 2–4-ternate/pinnate.		(19)
+	Leaves 1–2-ternate/pinnate (3–5-partite to 2-ternate).		(20)
19 (18)	Leaves with narrow ultimate segments 2–5 mm broad, hirtellous along the margins, lobes round, obtuse; primary umbel overtopped by laterals; bracteoles oblong to obovate, entire to 3-lobed at apex, lobes obtuse; petals white; fruit 4–5 mm.		19 Pleurospermum franchetianum
+	Leaves with ultimate segments 0.3–1 mm broad, margin glabrous, lobes lacerate, acute; primary umbel not overtopped by laterals; bracteoles oblanceolate, 3-lobed to pinnate/pinnatifid at apex, apex acute; petals white to pink; fruit 6–10 mm.		20 Pleurospermum benthamii
20 (18)	Leaves 3–5-partite (sometimes to 2-ternate).		(21)
+	Leaves 2-ternate/pinnate.		(22)
21 (20)	Leaves 3–5-partite (sometimes to 2-ternate); leaf bases and veins with coarse white hairs reminiscent of those of Heracleum; rays 2–4 cm; petals white.		17 Pleurospermum heracleifolium
+	Leaves always 3-partite, without white hairs; rays 5–6 cm; petals pink.		18 Pleurospermum macrochlaenum
22 (20)	Rays 10–18, 2–7 cm; bracteoles lanceolate, acute or 3-lobed; fruit smooth, wings sinuate but not irregularly dentate.		21 Pleurospermum decurrens
+	Rays 7–13. 1–2.5 cm; bracteoles linear-lanceolate, entire; fruits tuberculate with irregularly dentate wings.		22 Pleurospermum cristatum
23 (10)	Petiole wings greatly expanded, white with purple veining, upper leaves and bracts enveloping the inflorescence.		23 Pleurospermum amabile
+	Petiole wings not greatly expanded, not purple veined.		(24)
24 (23)	Leaves 1-pinnate to 2-pinnatifid; rays 2–4; bracteoles broadly ovate, entire.		24 Pleurospermum bicolor
+	Leaves 2–4-ternate/pinnate; rays (4–)6–25; bracteoles entire or more usually pinnatifid at apex.		(25)
25 (24)	Stems, petioles and leaf rachis conspicuously white pubescent.		26 Pleurospermum pilosum
+	Plants essentially glabrous, bases of umbels and/or petioles sometimes puberulent.		(26)
26 (25)	Calyx teeth conspicuous, triangular to lanceolate.		(27)
+	Calyx teeth obsolete or minute.		(34)
27 (26)	Ultimate leaf segments 5–20 mm broad, irregularly serrate or incised.		25 Pleurospermum yunnanense
+	Ultimate leaf segments finely dissected, 1–8(–10) mm broad.		(28)
28 (27)	Calyx teeth linear-lanceolate; sheaths of upper leaves and bracts broadly auriculate; bracteoles silvery white with a narrow green midrib, apex acuminate to 3-lobed.		27 Pleurospermum album
+	Calyx teeth triangular or rounded; leaf sheaths somewhat expanded but not auriculate; bracteoles usually white margined, but not conspicuously silvery white, apex usually pinnatifid.		(29)
29 (28)	Rays 4–7, very unequal; bracteoles entire, apex acuminate.		29 Pleurospermum rupestre
+	Rays (6–)8–20(–30), subequal (but see P. szechenyii); bracteole apex pinnatifid (rarely acuminate).		(30)
30 (29)	Rays (15–)20–30.		(31)
+	Rays 6–12(–15).		(32)
31 (30)	Plant without unpleasant odor when crushed; rays very unequal; fruit wings broad, sinuate but not dentate.		30 Pleurospermum szechenyii
+	Plant with a strong unpleasant odor when crushed; rays subequal; fruit wings broad, irregularly dentate.		9 Pleurospermum foetens
32 (30)	Leaf blades oblong-lanceolate in outline, approaching 2–3-ternate/pinnate; fruit wings broad, sinuate.		31 Pleurospermum wilsonii
+	Leaf blades broadly ovate in outline, 3–4-ternate/pinnate; fruit ribs prominent to winged, but not sinuate.		(33)
33 (32)	Ultimate leaf segments ca. 2 mm; calyx teeth ca. 1 mm, green.		32 Pleurospermum hookeri
+	Ultimate leaf segments 3–5 mm; calyx teeth ca. 0.3 mm, dark purple.		33 Pleurospermum tsekuense
34 (26)	Rays 5–9(–11); bracts and bracteoles entire, acuminate.		(35)
+	Rays (9–)11–25; bracts and bracteoles pinnate/pinnatifid at apex, rarely acuminate.		(36)
35 (34)	Stems and leaf sheaths purple-red, rays subequal; bracteoles broad, longer than the flowers.		35 Pleurospermum apiolens
+	Stems and leaf sheaths green, rays very unequal; bracteoles linear-lanceolate, shorter than the pedicels.		28 Pleurospermum simplex
36 (34)	Larger plants, 30–60 cm; rays 10–25; fruit wings broad, sinuate or irregularly cristate/dentate.		(37)
+	Small slender plants, 20–35(–45) cm; rays 9–15; fruit ribs prominent to narrowly winged, but not sinuate or dentate.		(38)
37 (36)	Rays subequal; fruit wings sinuate.		37 Pleurospermum linearilobum
+	Rays very unequal; fruit wings irregularly cristate/dentate.		39 Pleurospermum wrightianum
38 (36)	Rays 1.5–2.5 cm.		34 Pleurospermum giraldii
+	Rays 4–12 cm.		(39)
39 (38)	Stem branches often opposite or whorled; leaf rachis glabrous; ovary smooth.		36 Pleurospermum handelii
+	Stem branches usually alternate; leaf rachis tuberculate on abaxial surface; ovary tuberculate.		38 Pleurospermum calcareum