F.C. Stern A Study of the Genus Paeonia
3. P.Delavayi Franchet in Bull. Soc. Bot. France, 33, 382 (1886), et PI. Delavay. 31 (1889) ; Huth in Engl. Bot. Jahrb. 14, 273 (1892) ; Finet & Gagnepain in Bull. Soc. Bot. France, 51, 524 (1905), et Contrib. Fl. Asie Or. 1, 22i (1905), excl. var. ; Gard. Chron., Ser. 3, 53, 405, fig. 169 (1913) ; Grove & Forrest, ibid. 68, 97, fig. 41, 43, 44 (1920) ; Render, Man. Cult. Trees and Shrubs, 215 (1927) ; Handel- Mazzetti, Symb. Sinicae, 7, 266 (1931) ; Bean, Trees and Shrubs, 3, 265 (1933) ; F.C. Stern in Jown. Roy. Hart. Soc. 68, 125 (1943). Syn. P.Delavayi var. atropurpurea Schipczinsky in Not. Syst. Herb. Hort. Bot. PetroP.2, 47 (1921).
Description. A Shrub up to i -6 m. high, entirely glabrous. Leaves bitemate, 20-27 cm. long ; petiole 7-10 cm. long ; terminal set of 3 leaflets carried well away from the lateral sets on a common petiolule about 6 cm. long ; common petiolule of lateral sets of leaflets 1-2 cm. long ; leaflets dark green above, glaucous beneath ; terminal leaflet (of each set) 3-sect, the central segment deeply and spreadingly 3-lobed with the lobes entire or toothed, the lateral segments entire or slightly toothed, oblong-elliptic, acuminate, mostly 5-7 cm. long by 1-2 cm. broad ; lateral leaflets of terminal set deeply 4-5 lobed with sometimes an additional segment (almost free) at the base, leaflets of lateral sets much smaller than the others, 2-4-lobed or -toothed. Flower about 9 cm. across, with a conspicuous involucre of 8-12 foliaceous bracts set close against the five greenish sepals. Bracts persistent, ovate to lanceolate, tapering to the shortly- or long-acuminate apex, 2-5-6 cm. long X I-5-2 cm. broad. Sepals persistent, suborbicular, thinly leathery, apex acute to rounded, 2-2-5 cm. in diameter. Petals dark red, obovate, rounded, cuneate at base, 3-4 cm. long X 2-3 cm. broad. Stamens i -3-2 cm. long, filaments dark crimson, anthers yellow. Carpels i -5-2 cm. long, glabrous, conical, flask-shaped, long attentuated to the small circinnate stigma. Disc produced as conspicuous fleshy lobes 3-5 mm. high, around the base of the carpels. Follicles about 2 -5-3 cm. long and i -5 cm. wide.
Distribution. china : Yunnan, Li-kiang, Delavay 1142 (K), Forrest 2101, 5716 (K) ; Yung Ning, McLaren's collector 5(K).
Paeonia Delavayi is the tallest tree paeony other than P.suffruticosa and differs from the latter by the bracts which form an involucre immediately below the calyx, by the size of the petals, the glabrous leaves, shape of the leaf-segments and the absence of an enveloping sheath. The involucre below the calyx is unique among paeonies.
P.Delavayi was originally described by Franchet in 1886 from material collected by Pere Delavay in Yunnan in 1884. It was again collected by Forrest in 1910. The plants raised from collected seed differ somewhat in their habit of growth, and in the shade of colour and size of their flowers. Two definite forms can be distinguished ; one is a bush some 4 ft. high and about the same in diameter, with flowers of a deep maroon colour some 3 inches across; the other form is taller, up to 6 ft. high, with larger flowers of a redder shade of [end page 044] maroon. The latter is the finer form and received an Award of Merit from the Royal Horticultural Society in 1934.
There is a plant growing at Kew, raised from Chinese seed, with dull orange flowers which appears to be a natural hybrid between P.Delavayi and possibly P.lutea. Forrest in his note in the Gardeners' Chronicle, Ser. 3, 68, 97 (1920), refers to natural hybrids between these species. It would seem that all the species classed together under subsection delavayanae hybridise together when they are in contact in their natural habitat, and there are several specimens in herbaria which appear to be hybrids.
The cultivation of this paeony presents no difficulty. It will grow in the open or under good soil, either acid or limy. It flowers at the end of May and seeds freely. P.delavayi was first exhibited at a Flower Show in France in 1892. [end page 045]