The proper name of Paeonia lactiflora is: Cynanchum otophyllum

48. Cynanchum otophyllum (Botanical Nomenclature and Textual Examination) Thousand-Year-Old Sheng (Yunnan); Milk Vine (Sichuan); Paeoniae lactiflora (Chuxiong, Yunnan); Qingyang Ginseng, Qingyang Ginseng, Bai Cen (Kunming, Yunnan); Bai Qiqi, Bai Yao (Lijiang, Yunnan) Plate 136 (7-11)

Cynanchum otophyllum Schneid. in Sarg. Pl. Wils. 3: 347. 1916; Hand.-Mazz. Symb. Sin. 7: 997. 1936; Tsiang in Sunyatsenia 4: 117. 1939; Illustrated Catalogue of Higher Plants of China 3: 485, fig. 4924. 1974. --Cynanchum deltoideum Hook. f. Fl. Birt. Ind. 4. 24. 1883, non Hance in Ann. Sci. Nat. ser 5, 5. 228. 1866. --Vincetoxicum deltoideum O. Kuntze, Rev. Gen. Pars 1. 424. 1891.

Perennial herbaceous vine; roots terete, gray-black, ca. 8 mm in diam. Leaves opposite, membranous, ovate-lanceolate, 7-10 cm long, 4-8 cm wide at base, long acuminate at tip, y auriculate-cordate at base, auricles rounded, pendulous, pilose on both surfaces. Umbellate cymes axillary, bearing more than 20 flowers; calyx outside puberulent, with 5 glands on inner basal surface; corolla white, lobes oblong, inside puberulent; corona cupular, slightly longer than gynostegium, lobes with 1 small tooth in middle, or frilled or absent; pollinia 1 per locule, pendulous; stigma tip slightly bifid. Follicles double or only 1 developing, short lanceolate, ca. 8 cm long, 1 cm in diam., acuminate toward tip, base narrower, exocarp with straight stripes; seeds ovate, 6 mm long, 3 mm wide; seed hairs white silky, 3 cm long. Flowering June-October, fruiting August-November.