Paeonia Species Key

(based on D. Y. Hong: Peonies of the World, vol. 3, 2021, p.219-222)


Key / Info Name                  
1a Shrubs; disk fleshy and annular, enveloping only base of carpels or half-leathery, enveloping half to whole carpels until mid-anthesis subg. 1:
Moutan
2a Flowers usually 2-4 in a cyme, more or less pendent; disk fleshy, enveloping only base of carpels; carpels always glabrous sect. 1a:
Delavayanae
3a Carpels nearly always single, rarely 2; follicles 4.7-7cm long, 2-3.3cm in diameter; petals, filaments and stigmas always purely yellow 1 P. ludlowii
3b Carpels usually 2-5(-7); follicles less than 4cm long, 1.5cm in diameter; petals, filaments and stigmas often not purely yellow 2 P. delavayi
2b Flowers solitary, uprights; disk half-leathery, enveloping carpels halfway or completely until mid-anthesis; carpels tomentose or glabrous sect. 1b:
Moutan
4a Carpels glabrous, 2-5 in number; disk enveloping carpels halfway or up to base of styles until mid-anthesis; lower leaves decompound with (20-)25-54(-71) leaflets; leaflets all lobed
5a Carpels 5, very occasionally 4, in number; disk enveloping ovary up to halfway at anthesis; leaflets of lower leaves (35-)37-54(-71) in number; terminal leaflet elliptic or narrow-rhomboid, with length/width ratio (1.46-)1.62-2.18(-2.55) 3 P. decomposita
5b Carpels mostly 3, less often 4, 2 or 5 in number; disk enveloping whole overy at anthesis; leaflets of lower leaves (20-)25-37(-49) in number, terminal leaflet orbicular or wide-rhomboid, with length/width ratio (1.02-)1.03-1.57(-2.20) 4 P. rotundiloba
4b Carpels densely lanate or tomentose, 5(-7) in number; disk completely enveloping carpels until mid-anthesis; lower leaves biternate, biternate-pinnate or ternate-bipinnate, with leaflets usually fewer than 20(-33), if more, at least some of them entire
6a Lower leaves with 9 leaflets ovate or ovate-orbicular, only terminal leaflets usually 3-lobed, often reddish above; petals often with a reddish blotch at base 8 P. qiui
6b Lower leaves with more than 9 leaflets, if 9, then leaflets mostly lobed; leaflets green above; petals without a blotch, or with a large, dark purple blotch at base
7a Lower leaves with 11-33 leaflets; leaflets usually ovate to lanceolate, mostly entire, less frequently ovate-orbicular and mostly lobed
8a Lower leaves with 11-15 leaflets; leaflets ovate to ovate-lanceolate, mostly entire; petals white, rarely pale pink, without a blotch 6 P. ostii
8b Lower leaves with (17-)19-33 leaflets; leaflets lanceolate or ovate-lanceolate and mostly entire, or ovate to ovate-orbicular and mostly lobed; petals white, rarely red, always with a large, dark purple blotch at base 5 P. rockii
7b Lower leaves with 9 (occasionally 11 or 15 in P. jishanensis) leaflets; leaflets ovate, ovate or nearly orbicular, mostly or all lobed
9a Leaflets ovate, terminal leaflets 3- or 5-cleft, with additional 1 to several lobes, lateral leaflets mostly 2- or 3-lobed, less frequently entire; lobes acute at apex; leaf blade glabrous on lower surface; sepals all caudate or mucronate 9 P. cathayana
9b Leaflets ovate-orbicular to orbicular, all 3-cleft; segments lobed, acute to rounded at apex; leaf blade villose along veins on lower surface; sepals all rounded at apex 7 P. jishanensis
1b Herbs; disk fleshy and short, enveloping only base of carpels
10a Petals nearly equal in size to, or smaller than, sepals; disk dentate, almost interrupted; lower leaves ternate or biternate, with 3 or 9 leaflets; lateral roots slightly fusiform sect. 2e:
Onaepia
11a Lower leaves biternate, with 55-110 leaf segments and final lobes; segments or lobes acute to rounded at apex; carpels usually 5, rarely 3, 4 or 6 in number; sepals exceeding petals 10 P. brownii
11b Lower leaves ternate, with 30-78 leaf segments and final lobes; segments orlobes mostly acute at apex; carpels usually 3, rarely 2 or 4 in number; sepals slightly smaller than, or subequal to, petals 11 P. californica
10b Petals much larger than sepals; disk annular, waved or flat; lower leaves biternate or triternate, with 9 or more leaflets; lateral roots carrot-shaped or fusiform
12a Flowers 2-4 in a cyme, less frequently solitary but with 1-2 undeveloped flower buds at axils, rarely simply solitary; sepals mostly caudate at apex; leaf blade usually with bristles along veins above sect. 2a:
Albiflora
13a Leaf blade cartiloginous and denticulate on margin, pubescent along veins or glabrous beneath; carpels glabrous, very rarely hairy 12 P. lactiflora
13b Leaf blade smooth on margin, glabrous beneath; carpels glabrous or hairy
14a Lower leaves with 70-140 leaflets/leaf segments; petals red, rarely pal rose, very occasionally white
15a Plants (60-)66-103(-120) cm tall; flowers usually simply solitary, less frequently- solitary but with 1 or 2 undeveloped flower buds, very rarely 2; carpels mostly 5, less frequently 4, rarely 3 15 P. anomala
15b Plants (24-)34-59(-71) cm tall; flowers mostly 2 or 3, less frequently 4 or solitary but with 1 or 2 undeveloped flower buds, occasionally simply solitary; carpels mostly 3 or 2, rarely 4 or 1 15a P. veitchii
14b Lower leaves with fewer than 30 leaflets or leaf segments; petals white, rarely pale rose
16a Carpels 1, rarely 2 in number, mostly tomentose, less frequently glabrous; flowers often several per stem 13 P. emodi
16b Carpels mostly 2 or 3 in number, rarely 4, always glabrous; flowers nearly always solitary, rarely 2 in number, but sometimes with 1-2 undeveloped flower buds at axils 14 P. sterniana
12b Flowers always solitary and terminal; sepals mostly rounded at apex; leaf blade glabrous or with bristles along veins above
17a Tab roots not thickened, lateral roots always fusiform; lower leaves with mostly more than 20, rarely fewer, leaflets or leaf segments; leaf blade covered with bristles along veins above, or, if glabrous above, nearly always villose beneath sect. 2b:
Paeonia
18a Stems mostly hirsute; sepals mostly hairy on abaxial side; leaflet blade always glabrous or rarely villose at base above, more or less villose beneath
19a Lower leaves with mostly more than 20, very rarely as few as 11, leaflets or leaf segments; leaflet blade linear-elliptic or lanceolate; sepals hispidulous or glabrous on abaxial side 33 P. officinalis
19b Lower leaves with mostly fewer than 20, occasionally up to 32, leaflets or leaf segments; leaflet blade elliptic, oblong or ovate-lanceolate; sepals densely villose on abaxial side
20a Flowers rose to red; anthers yellow; lower leaves with 11-25, occasionally up to 32, leaflets or leaf segments 31 P. arietina
20b Flowers dark purple; anthers orange; lower leaves with 9-15, occasionally up to 25, leaflets or leaf segments 32 P. parnassica
18b Stems glabrous; sepals always glabrous; leaflet blade mostly with bristles along veins above
21a Leaflets or leaf segments always dentate-lobed, with lobes less than 1cm long stigmas yellow or pale pink 29 P. peregrina
21b Leaflets or leaf segments entire or rarely deeply lobed; stigmas red
22a Lower leaves with 19-45 leaflets or leaf segments; leaf blade hispidulous beneath 30 P. saueri
22b Lower leaves with more than 70 leaflets or leaf segments; leaf blade always glabrous beneath
23a Leaflets or leaf segments of lower leaves 130-340 in number, mostly filiform, 0.5-8mm wide 28 P. tenuifolia
23b Leaflets or leaf segments of lower leaves 70-100 in number, linear, 4-18mm wide 27 P. intermedia
17b Tab roots carrot-shaped; lower leaves with no more than 24 (only in P. broteri up to 32 and in P. clusii 23-95) leaflets or leaf segments; leaf blade always glabrous above
24a Leaflets 9 or 13-24 (including leaf segments); carpels mostly 2 or 3, rarely 1, 4 or 5 sect. 2c:
Obovatae
25a Leaflets 9, entire; carpels glabrous 16 P. obovata
25b Leaflets mostly segmented, forming 13-24 leaflets or segments; carpels yellow papillate to hispidulous, rarely glabrous 23 P. mairei
24b Leaflets 9, rarely 8 or 7, or leaflets/leaf segments up to 95; carpels 2-5, rarely 6, 1, 7-10 sect. 2d:
Corallinae
26a Leaflets plus leaf segments of lower leaves 23-95 in number, linear to ovate 20 P. clusii
26b Leaflets plus leaf segments of lower leaves less than 21 (up to 32 in P. broteri), broad elliptic to obovate
27a Lower leaves with 9 or fewer leaflets; carpels always glabrous 17 P. cambessedesii
27b Lower leaves with usually 10-15, less frequently 9 or more, leaflets plus leaf segments; carpels mostly tomentose
28a Carpels 1, less frequently 2, nearly always glabrous, very occasionally sparsely hairy; follicles columnar, 4-5.4cm long 26 P. algeriensis
28b Carpels (1)2-4, rarely more, tomentose or glabrous; follicles long-ovoid or ellipsoid, up to 4cm long
29a Styles 1.5-3.5mm long; lower leaves with 11-14, rarely up to 17, leaflets or leaf segments; leaf blade densely or sparsely villose beneath; carpels always glabrous 24 P. kesrouanensis
29b Styles usually absent (only in P. corsica 1.5-3mm long); lower leaves with 9-20 leaflets or leaf segments; leaf blade glabrous, sparsely hispid, puberulent or villose beneath; carpels tomentose or glabrous
30a Carpels always lanate or tomentose with hairs 2-3mm long; styles absent
31a Leaflets usually entire; lower leaves with 9, rarely 10, very occasionally 11, leaflets; leaflet blade usually obate, rounded, nearly truncate with a mucro, or rounded, less frequently acute at apex 21 P. daurica
31b Leaflets at least some segmented; lower leaves with usually 10 or more, very occasionally 9, leaflets or leaf segments; leaflet blade usually acute at apex
32a Lower leaves with mostly (11)15-21, rarely up to 32, leaflets or leaf segments; leaflets 4-10(-15) cm long, 1.5-5(-6.5) cm wide, always glabrous; carpels with hairs 2mm long 19 P. broteri
32b Lower leaves with mostly (9)11-15, rarely up to 21 leaflets or leaf segments; leaflets 9-18cm long, 4.5-9cm wide, sparsely hispid or glabrous; carpels with hairs 3mm long 22 P. mascula
30b Carpels glabrous or tomentose with hairs 1.5mm long; styles present or absent
33a Carpels tomentose, rarely glabrous; lower leaves with usually 9, rarely up to 20 leaflets/leaf segments; leaflet blade holosericeous beneath; styles 1.5-3mm long 18 P. corsica
33b Carpels glabrous, very occasionally sparsely hairy; lower leaves with 10-15 leaflets/leaf segments; leaflet blade glabrous, very occasionally sparsely hairy (hairy leaves always accompanied by hairy carpels); styles lacking 25 P. coriacea


P. rockii - Subspecies
Key / Info Name                  
1a Leaflets lanceolate to ovate-lanceolate, all or mostly entire 5a P. rockii subsp. rockii
1b Leaflets ovate to ovate-orbicular, all or mostly lobed 5b P. rockii subsp. atava


P. obovata - Subspecies
Key / Info Name                  
1a Leaves mostly glabrous or sparsely (occasionally densly) hispid on lower surface; diploid (tetraploids rarely occur in the Far East of Russia and on Mt Changbai of NE China) 16a P. obovata subsp. obovata
1b Leaves usually densely, very occasionally sparsely, hispid on lower surface; tetraploid (the only diploid found in a mixed population in Lushi County, W Henan) 16b P. obovata subsp. willmottiae


P. clusii - Subspecies
Key / Info Name                  
1a Leaf segments 23-95 in number, linear to lanceolate, up to 2.6cm, very occasionally 3.2cm 20a P. clusii subsp. clusii
1b Leaf segments 23-48 in number, lanceolate to ovate, 2.5-4.5cm wide 20b P. clusii subsp. rhodia


P. daurica - Subspecies
Key / Info Name                  
1a Sepals often villose on the abaxial side; leaves rather densely villose on the lower side 21f P. daurica subsp. velebitensis
1b Sepals glabrous; leaves sparsely villose or puberulous, less frequently densely villose on the lower side or glabrous
2a Carpels glabrous or nearly glabrous; petals yellow
3a Leaves densely villose and thus greyish beneath 21c P. daurica subsp. macrophylla
3b Leaves usually sparsely villose beneath 21g P. daurica subsp. wittmanniana
2b Carpels tomentose; petals red, rose, white or yellow
4a Leaflets or leaf segments puberulous or glabrous beneath, obovate, apex rounded or obtuse, often with a short mucro 21d P. daurica subsp. mlokosewitschii
4b Leaflets or leaf segments villose or glabrous beneath, obovate, oblong or wide-elliptic, apex rounded to short-acuminate
5a Petals red or rose; leaves glabrous or sparsely villose beneath
6a Leaflets or leaf segments broad-obovate, truncate to rounded at apex 21a P. daurica subsp. daurica
6b Leaflets or leaf segments obovate to oblong, rounded to acute at apex 21b P. daurica subsp. coriifolia
5b Petals yellow or yellowish white, but sometimes red at periphery or with a red spot at base; leaves villose beneath
7a Leaves mostly densely villose and thus greyish beneath 21c P. daurica subsp. tomentosa
7b Leave usually sparsely villose beneath 21g P. daurica subsp. wittmanniana


P. mascula - Subspecies
Key / Info Name                  
1a Flowers red or pink (entire range except some Aegean islands, Canakkale Province (NW Turkey, Sicily (Italy) and Calabria (Italy)) 22a P. mascula subsp. mascula
1b Flowers mostly white, rarely red or pink
2a Leaves nearly always hispid, very rarely glabrous beneath (Sicily and Calabria) 22d P. mascula subsp. russoi
2b Leaves mostly glabrous, rarely very sparsely hispid beneath
3a Leaflets plus leaf segments of lower leaves 9-11 in number, 13-17.5 x 7-9cm (Canakkale) 22b P. mascula subsp. bodurii
3b Leaflets plus leaf segments of lower leaves (9-)11-14(-21) in number, 9-13 x 4.5-7.5cm (S Greece and Aegean islands) 22c P. mascula subsp. hellenica


P. officinalis - Subspecies
Key / Info Name                  
1a Carpels glabrous, occasionally sparsely hirsute; sepals mostly glabrous; leaflets or leaf segments usually obtuse at the apex, often lobed; stems mostly glabrous 33e P. officinalis subsp. microcarpa
1b Carpels tomentose; sepals ususally pubescent; leaflets or leaf segments usually acuminate at apex, entire, rarely lobed; stems hirsute or glabrous
2a Leaflets plus leaf segments 11-24 in number, 2-4.5cm wide, glabrous or sparsely villose beneath; sepals glabrous or sparsely pubescent 33b P. officinalis subsp. banatica
2b Leaflets plus leaf segments 19-130 in number, 1-3cm wide, always villose beneath; sepals always pubescent
3a Leaflets plus leaf segments 35-130 in number, always with some lobed, 1-2cm wide 33c P. officinalis subsp. huthii
3b Leaflets plus leaf segments 19-45 in number, all entire or occasionally very few lobed, 1-3cm wide
4a Leaves villose-floccose beneath, hairs flattened at base 33d P. officinalis subsp. italica
4b Leaves hairy but never villose-floccose beneath, hairs cylindrical 33a P. officinalis subsp. officinalis


© Copyright   Dr. Juerg Plodeck , 2023