Ohwi, J. (1953)

Flora of Japan (English Translation 1965) :

Paeonia pp.460-461, Smithsonian Institution, Washington

Flora of Japan

Paeonia L. Botan Zoku

Perennial herbs or suffruticose subshrubs,; leaves ternately or pinnately compound; flowers large, terminal and axillary, pale pink, yellow or purple red. Sepals 3-5, herbaceous, greenish; petals 5-20, petaloid, without nectary glands, deciduous; stamens many, carpels 3-5, free, follicles rather large, several- to many-seeded; seeds black.——About 30 species in the Old World, mainly in Asia. 2 in N. America.

1A			Plants herbaceous, the flowers with a low disc below the carpels
	2A		Leaflets rather thin, not shining. oblong, usually not decurrent below, abruptly acute to subobtuse, whitish beneath; flowers not fully expanded; filaments pale red, stigmas purplish, plants of mountains.
		3A	Flowers white, stigma short, slightly recurved, follicles reflexed	1. P. japonica
		3B	Flowers rose, stigma rather elongate, prominently circinnate, follicles spreading	2. P. obovata
	2B		Leaflets firm, cartaceous, shining above, narrowly obovate or lanceolate, often decurrent on the petiolules, usually acuminate, pale green beneath, flowers fully expanded; cultivated	3. P. lactiflora
1B			Plants shrubby, the flowers with the disc dilated and enveloping the carpels, cultivated.	4. P. suffruticosa

1. Paeonia japonica (Makino) Miyabe & Takeda. P. obovata var. japonica Makino - Yama shaku-yaku. Stems 40-50 cm long, with few scalelike leaves at base; rhizomes Stout, short: cauline leaves 3-4, petiolate, large, usually twice ternate, the leaflets oblong to obovate, 4-12 cm long, 3-7 cm wide, abruptly acute to obtuse, acuminate at base, often petiolulate, glaucous beneath; flowers white, 4-5 cm- across, solitary and terminal; sepals ovale; petals 5-7, ascending, connivent above, obovate, 3-4 cm. long; anthers 5-7 mm. long; stigma short, slightly recurved. - Apr-June. Thickets and open woods in mountains; Honshu, Shikoku, Kyushu.

Var. pilosa Nakai. Ke-yama-shakuyaku. Leaves pubescent beneath. - Occurs with the typical phase.

2. Paeonia obovata Maxim. Benibana-yama shakuyaku. Closely allied to the preceding; leaves scattered soft-pubescent beneath; flowers pale rose; stigma elongate, circinnate. - Apr.-June. Woods and thickets in mountains; Hokkaido, Honshu, Shikoku. - Korea, Manchuria, China, Amur, and Sakhalin.

Var. glabra Makino. Ke-nashi-benibana-yama-shakuyaku. Leaflets, glabrous beneath, - Occurs with the typical phase.

3. Paeonia lactiflora Pall. P. albiflora Pall. - Shaku-yaku. Erect perennial herb, 50-80 cm. high, the roots thickened, narrowly fusiform; leaves once to twice pinnately ternate, the leaflets often 3-parted, the segments lanceolate to narrowly obovate, shining above, pale green beneath; flowers large, white to rose or red-purple, often double. - May. Long cultivated in our area for ornament and medical purposes. - c-Siberia, Manchuria, Korea, China, and Tibet.

4. Paeonia suffruticosa Andr. P. moutan Sims - Botan. Sparsely branched small shrub 1-1,5 m. high; leaflets usually 3- to 5-cleft, often whitish beneath; flowers large and showy, the disc thick- membranous, enveloping the carpels; carpels densely brown-pubescent. - Long cultivated in our area and many cultivars of it are grown. - nw. China, Tibet, and Bhutan.