Book  (2011)  Page(s) 44-47.  Includes photo(s).
 
Paeonia obovata Maxim., Prim. Fl. amur. 29 (1859).
Paeonia japonica (Makino) Miyabe & Takeda; P. oreogeton S. Moore; P. vernalis Mandl.
Herbs perennial, 30-70 cm tall. Roots thick, carrot-shaped. Caudex usually short, 2-8 cm long. Stems often single, always single, glabrous. Lower leaves spreading or ascending, biternate; leaflets 9, entire, obovate, cuneate at the base, rounded or acute at the apex, 5-20 cm long, 4-14 cm wide, glabrous above, glabrous to densely hispid beneath. Flowers solitary, terminal. Involucrate bracts 1 or 2, leaf-like, rarely lacking. Sepals 2-4, but mostly 3, mostly rounded at the apex. Petals 4-7, spreading or incurved, white, rose, pink-red, red, purple-red, or rarely white with pinkish base or margins, obovate, 3-5.5 cm long, 1.8-2.8 cm wide. Filaments white, whitish-yellow, or purple below but white above to entirely purple; anthers yellow, orange-red or dark purple. Disk yellow, waved, 1-1.5 mm high. Carpels mostly 2 or 3, always glabrous; styles 2-5 mm long; stigmas red. Follicles gradually recurved, ellipsoid, 2-3 cm long. Seeds black, glossy, ovoid-spherical, 6-7 mm long, 5-6 mm in diameter. Distributed in East Asia. Two subspecies:

Leaves mostly glabrous or sparsely (occasionally hispid on lower surface; diploid (tetrapoids rarely occur in the Far East of Russia and on Mt Changbai of NE China) ....subsp. obovata
Leaves usually densely, very occasionally sparsely, hispid on lower surface; tetraploid (the only diploid found in a mixed population in Lushi County, W Henan)....subsp. willmottiae

Paeonia obovata Maxim. subsp. obovata...
Flowering from late April to early June; fruiting from late July to August. Chromosome number: 2n = 10, rarely 2n = 20. Growing in deciduous broad-leaved, mixed broad-leaved and needle-leaved, or conifer forests below 2,800 m in altitude.

Book  (2011)  Page(s) 449.  
 
P. obovata Maximowicz. Illustration: Gardeners' Chronicle 57:290.f.94 (1915); Botanical Magazine. 8867 (1916); National Horticultural Magazine 13:227 (1934).
Stem hairless. 40-60 cm. Leaves usually 3. Lower leaves twice divided into 3, with broadly elliptic lateral leaflets and a terminal usually obovate one, all acute or shortly acuminate, hairless above, sparsely or densely hairy beneath with long hairs. Flowers 7-10 cm across, petals white or rose-purple. Filaments greenish white or purple. Carpels 2-5, hairless. E. Asia...Early summer.
Var. obovata. Leaves sparsely hairy beneath. Flowers to 7 cm across; petals red. Filaments greenish white. SE Siberia, Manchuria, E China, Sakhalin, Japan.
Var. japonica Makino (P. japonica (Makino) Miyabe & Takeda). leaves sparsely hairy beneath. Flowers c. 7 cm across; petals white. Filaments dark purple. Japan.

Book  (2010)  Page(s) 31.  
 
We often found P. obovata and P. mairei plants with single stems...

Book  (2010)  Page(s) 137-148.  Includes photo(s).
 
Paeonia obovata....Hong et al., 2001 have explained clearly why Paeonia japonica and the other taxa were treated in synonmy. Makino (1898: 302) did not designate type for his new variety, var. japonica, se we designated Miyabe and Takeda's figure as neotype. ...

Book  (2005)  Page(s) 54-55.  
 
Paeonia obovata
This is one of the most widespread species of peony, which occurs in China, Japan, North and South Korea and the island of Sakhalin. It obtained its name from the unusual shape of its terminal leaflets, which are broader towards the tip than at the base, in other words obovate.
It is a robust plant with glabrous stems and grows to a height of approximately 60 cm (24 in.), with solitary pink, white or red flowers. The biternate leaves have 7-9 leaflets, which are dark green and glabrous above and slightly glaucous beneath, with a scattering of simple hairs. The lower leaves are unequal with oval or oblong lateral leaflets and larger terminal leaflets; both are cuneate at the base and acuminate at the tips. The white var. alba is the most readily available. Plants can be diploid or tetraploid [subspecies willmottiae] (2N=10 or 20)....Paeonia obovata can be grown under deciduous trees as long as it gets full sunshine for at least part of the day. It will also grow in the open, but needs to be provided with some shade from hot afternoon sun. Both of the white-flowered forms come true from seed.

Book  (2004)  Page(s) 106-109.  Includes photo(s).
 
P. obovata Maximowicz, Primitiae Florae Amurensis 29 (1859).
Epithet: obovata, "obovate", referring to the shape of the terminal leaflet.
Key to the subspecies of P. obovata
Larger, to 70 cm (28 in.), leaves sparsely villow below, flowers as for species....Subsp. obovata
Smaller, to 50 cm (20 in.), leaves glabrous, flower white.....Subsp. japonica

P. obovata subsp. obovata

Description: Stem 40-70 cm (16-28 in.) tall, glabrous. Lower leaves biternate; leaflets unequal, terminal usually obovate, laterals broadly oval or oblong, all shortly acuminate at the apex, cuneate or widely cuneate at the base, mostly 5-12 x 3.5-7 cm (2-4.75 x 1.4-2.75 in.), in fruit up to 15 x 9 cm (6 x 3.5 in.), thinly papery, dark green and glabrous above, glaucous and sparsely villous below. Flowers white to rose-purple, up to 8 cm (3 in.) across. Stamens 17 mm long, filaments white or rose, anthers yellow. Carpels two or three, glabrous, 2 cm (0.75 in.) long, attenuated, stigma conspicious, 5 mm across. Follicles 30-35 mm long. 2n = 10, 20.
Distribution: Russia, in the Far East (Udsk, Ussuri, and Zee-Buryat.), the Amur region, Manchuria, the Kurile Islands, and Sakhalin; Korea; China, provices of Shanxi, Sichuan, and Yunnan; and Japan. It grows in oak, birch, and mixed forests, on open slopes, and on riverbanks up to 2000 m (6600 ft.) elevation.

Article (magazine)  (2001)  Page(s) 123-136.  
 
Leaf orientation...was considered by Ding and Liu (1991) as an important character for distinguishing P. japonica (spreading) from P. obovata (ascending. According to our field observations, however, this character is unstable even within a population....
Leaf indumentum. This character was used by Japanese botanists for recognizing infraspecific taxa both in Paeonia obovata (var. typica and var. glabra) and P. japonica (var. japonica and var. pilosa). We examined hundreds of specimens, both in the field and herbaria, and found that leaf indumentum on the lower surface was an extremely variable character, from entirely glabrous to densely hirsute or pubescent..... the recognition of Paeonia obovata var. glabra and P. japonica var. pilosa based on leaf indumentum is unreasonable. In addition, we examined hundreds of herbarium specimens from China, Japan and the Korea Peninsula and projected their indumentum states onto the distribution map of the complex (Fig. 3). It can be seen that leaf indumentum is correlated to some extent with the geographical distribution and ploidy. The plants of this complex in W. Hubei, NW. Sichuan. N. Chongqing, Shaanxi, Shanxi, and W. Henan are all tetraploid and nearly always densely hirsute or pubescent except those in Shanxi, which were variable from mostly hairy (e.g. Hong et al. H98009) to mostly glabrous or sparsely hairy (e.g. Hong et al. H98010)....
Sepals. They exhibit the least variation, are nearly always 3, very occasionally 2 or 4 in number and mostly rounded at the top....
The most important character used for distinguishing P. japonica from P. obovata is the colour of petals, rose-purple in P. obovata and white in P. japonica. Our extensive observations revealed that the colour pattern in this complex is not so simple, but actually varies from purely white ...., white with pinkish shade at the base or periphery....in W. Henan, rose ...., pink-red ...., red .... purple-red ....to purple-red with two white stripes on the back...
The orientation of petals was said by Ding and Liu (1991) to be a valuable character for distinguishing white-flowered P. japonica (ascending) from red-flowered P. obovata (spreading). However, the two orientations could be found in each species....
Petals are usually 5 or 6, but flowers with 4 ...or 7 petals...occasionally occur. Even within a population....the number of petals varied from 4 to 6....
The number of stamens was used by Ding and Liu (1991) as an important character in distinguishing P. japonica (100-280) from P. obovata (14-75). Our extensive observations did not confirm this......the number of stamens varied from (58) 70 to 230 in the white-flowered form (P.japonica), and from 21 to 110 in the red-flowered form (P. obovata). Although there is some difference in number of stamens between the two colour forms, the two ranges overlap much. Therefore, as number of stamens varies continuously in the complex, this is not a diagnostic character for distinguishing the two colour forms as separate species....
The number of carpels was found to vary from 1 to 5, usually 2 or 3 in both the white-flowered and red-flowered forms....
According to Ding and Liu (1991), the orientation of mature follicles can be used for distinguishing P. obovata (strongly recurved) and P. japonica (slightly recurved). However, follicles recurve gradually during ripening and the two states can be found in both P. obovata and P. japonica....
....diploids and tetraploids occur in both the white-flowered (P. japonica) and the red-flowered form (P. obovata). Therefore, the chromosome data do not support the recognition of P. japonica as an independent taxon. However, ploidy level is shown to be correlated with the geographical distribution. Nearly all the populations sampled are tetraploids in the western part of distribution area of the complex: Shanxi, Shaanxi. NW. Sichuan. N. Chongqing, W. Ik-nan and W. Hubei... But there are two exceptions: In Lushi County, W. Henan, there is a mixed population....in which both red-flowered and white-flowered forms were found to grow together, and both 2n= 10 and 2n = 20 were counted....
....it is justified to recognize only one species in the complex, P. obovata, with two subspecies: the typical subspecies for the populations in the northern, eastern and southern parts of the distribution range, which are diploid (very occasionally tetraploid in the Far East of Russia and in the Changbai Mountains, Jilin, China) and mostly glabrous to moderately pubescent or hirsute, and the subspecies willmottiae for the populations in the western part of the distribution range, which are tetraploid (diploid and tetraploid only in one mixed population in Lushi County, W. Henan Province), and mostly densely (less frequently moderately) hirsute or pubescent.

Book  (2001)  
 
Paeonia obovata Maximowicz, Prim. Fl. Amur. 29. 1859.
cao shao yao
Herbs perennial, 30--70 cm tall. Roots thick, attenuate toward tip. Stems glabrous. Proximal leaves spreading or ascending, 2-ternate; leaflets obovate, 5--14 × 4--10 cm, glabrous to densely pubescent or hirsute abaxially, glabrous adaxially, base cuneate, margin entire, apex rounded or acute. Flowers solitary, terminal, single, 7--12 cm wide. Bracts 1 or 2, unequal. Sepals (2 or)3(or 4), unequal, 1.5--3 × 1.5--2 cm, apex mostly rounded. Petals 4--7, spreading or incurved, white, rose, pink-red, red, purple-red, or rarely white with a pinkish base or margin, obovate, 3--5.5 × 1.8--2.8 cm. Filaments white, green-yellow, or purple proximally and white distally to wholly purple; anthers yellow, orange-red, or dark purple. Disc yellow, annular. Carpels (1 or)2 or 3(--5), glabrous; ovary green. Stigmas red. Follicles gradually recurved, ellipsoid, 2--3 cm. Seeds black, glossy. Fl. May--Jun, fr. Sep.
Deciduous broad-leaved, mixed broad-leaved, and coniferous forests; 200--2800 m. Anhui, SE Gansu, N Guizhou, Hebei, Heilongjiang, SE and W Henan, W Hubei, NW Hunan, N Jiangxi, E Jilin, Liaoning, SE Nei Mongol, S Ningxia, E Qinghai, S Shaanxi, Shanxi, Sichuan, NW Zhejiang [Japan, Korea, Russia (Far East)].

1 Leaves abaxially usually glabrous or sparsely (rarely densely) pubescent or hirsute subsp. obovata
+ Leaves abaxially usually densely (rarely sparsely) pubescent or hirsute subsp. willmottiae

Book  (2001)  Page(s) 1331.  
 
Paeonia japonica (Makino) Miyabe & Takeda in Gard. Chron. 48 (1910) 366.
Paeonia obovata Maxim. var. japonica Makino in Bot. Mag. Tokyo 16 (1902) 59.
Japanese. yama-shakuyaku.
Japan, Korea, China.
var. pilosa Nakai in J. Jap. Bot. 13 (1937) 395.
Japanese. ke-yama-shakuyaku; Korean. hinhambagggot, baegdzagjag.
Japan, Korea.
In Korea cultivated for medicinal purposes. The roots are used medicinally.
Ref.: Hammer et al. 1989, 193.

Book  (2001)  Page(s) 1331.  
 
Paeonia obovata Maxim., Prim. fl. amur. (1859) 29.
Japanese. benibana-yama-shakuyaku; Korean. sanhambagggot.
Japan, Korea, China, Russia (Uda, Amur, Sakhalin).
In Korea grown as medicinal plant. The roots are used medicinally.
ref.: Bail et al. 1986, 69.