Shrubs up to 1.5 m tall. Stems brown-grey. Lower leaves ternate-pinnate, with 11—15 leaflets; leaflets lanceolate to ovate-lanceolate, mostly entire, terminal leaflets often 2-3-lobed, very occasionally 1-2 lateral leaflets also 2—lobed, rounded at the base, acute to acuminate at the apex, 5—13 cm long, 2.5—6 cm wide, glabrous on both surfaces but sometimes pubescent at the base or the lower part of major veins above. Flowers solitary, terminal, single; involucrate bracts 3—6 in number, green, leaf-like; sepals 4—6 in number, green-yellow, broad-elliptic or ovate-orbicular, 1.5-3.1 cm long, 1.5—2.5 cm wide, shortly caudate or acute at the apex; petals usually 11-14 in number, white, rarely pinkish, obovate, 5.5-8 cm long, 4-6 cm wide, entire or incised at the apex; filaments purple-red; anthers yellow; disk entirely enveloping carpels at anthesis, purple—red, leathery, dentate or lobed at the apex; carpels 5, densely tomentose; stigmas sessile, red. Follicles oblong, densely brown-yellow tomentose. Seeds brown—black, oblong—spherical or spherical, 8—9 mm long, 7-8 mm in diameter.
Chromosome number: 2n=10 (diploid)
In deciduous broad-leaved forests and thickets on slopes at an altitude of 300-1 ,600 m.
Native in Anhui (Chaohu) and W Henan (Lushi County and Xixia County); cultivated in Anhui, Henan, Hubei, Shaanxi, Sichuan, and other provinces. This species is widely but sporadically cultivated in China as a traditional medicine.
The distinctive characters of Paeonia ostii are its ternate-pinnate lower leaves, with the leaflets 11-15 in number and ovate, ovate-lanceolate, mostly entire; flowers single and pure white, rarely pale pink; filaments red-purple; disk dark purple and stigmas red.
Paeonia ostii is considered a distinct species, but had been confused with P. suffruticosa subsp. suffruticosa (Pan, 1979). We have compared P. ostii to plants commonly cultivated for mudanpi (a famous Chinese traditional medicine) in Tongling, Anhui Province, the locality in which mudanpi is famously cultivated. They resemble each other very closely, and thus the plant commonly cultivated for mudanpi should be identified as P. ostii. Paeonia ostii is cultivated on a large scale in Tongling, Anhui Province, and to a lesser extent in other provinces such as Henan, Hubei, Shaanxi and Sichuan.
HONG Tao and his co-workers (Hong et al., 1992) stated that the shrub from which the type was collected was introduced from “Songxian, Yangshan, 1,200 m, in thickets on slopes”. We visited Songxian, Mt Yangshan, in Henan Province twice, in 1994 and 1997, and searched extensively for P. ostii in the mountains. We did find the species cultivated in Secaogou Village, but not in the wild. In 1998, however, we found it in Western Henan in Lushi County (D. Y. Hong et al. H98005).
We here designate a neotype for Paeonia ostii, since the original material cited in the protologue (Hong & Zhang, 1992) was not preserved. The protologue stated that it had been preserved in CAF but the keeper of the herbarium could not ﬁnd it, and was told by HONG Tao that no holotype specimen had been preserved.
- Hong, De-Yuan. “Peonies of the World. Taxonomy and phytogeography.” Kew: Royal Botanic Gardens, 2010, pp. 84-86.