Paeonia delavayi

Appearance

''Paeonia delavayi'' is a deciduous hairless shrub of ¼-1¾ m high. Plants have creeping stolons and the roots are thick because they are fused together. It mainly reproduces by growing into large clones like this. Young twigs are light green, or tinged purple, rarely branching, erect, generally on top of perennial, stick-like, grayish to light brown stems. In lower plants, woody parts may not be present above ground. Like all diploid peonies, it has ten chromosomes .

Naming

''Paeonia delavayi'' is closely related to ''P. ludlowii''. It can be distinguished easily because it reproduces mainly by stolons, has fused roots, stems emerge from the ground individually, is only up to 1¾ m high, has segmented leaves with narrow and acute segments, variously colored petals, stamens, disk, and stigmas, has two to eight carpels, which develop in small follicles and rarely produce seeds. ''P. ludlowii'' on the other hand can only reproduce by seed and lacks creeping underground stems, has slender, regular roots, while the stems form a clump, grows to 2-3½ m high, has leaves with short and suddenly pointed lobes, petals, stamens, disk and stigmas are always yellow, only one or very rarely two carpels develop but this grows into a much larger follicle which always develops seeds.''Paeonia delavayi'' is named after Father Jean Marie Delavay, a French Catholic missionary in China, who collected plants.

Distribution

''Paeonia delavayi'' is endemic to southwestern China, where it is limited to Sichuan, Yunnan and the very South-East of Tibet.

Status

''P. delavayi'' has been listed as endangered by the China Plant Red Data Book, and may be under threat if digging out roots for medicine on a large scale is not adequately controlled. However, because it easily reproduces vegetatively and is relatively widely distributed, it may not go extinct shortly if overexploitation of the root for medicine will be adequately controlled.

Habitat

''Paeonia delavayi'' almost exclusively reproduces through stolons, and seedlings are rare to find. This allows for rapid colonization after a seed has arrived at a new location, such as on newly stabilized debris. In combination with its thick roots this makes this species well adapted to colonize open habitat, that may be prone to drying out quickly. Local populations may consist of only one clone. It grows in light shade such as moist ''Picea likiangensis'' forest or dry and open ''Pinus densata''-''Quercus gilliana'' forest, and sometimes on grassy slopes or in glades. It grows at 2000-3600 m altitude. Insects feed on the fruits and limit seed development.

Evolution

''P. delavayi'' with maroon-red and ''P. lutea'' with yellow flowers, both from Northwest Yunnan were described respectively by Franchet and Delavay, on the same page of the same scientific article in 1886. In 1904 Finet and Gagnepain thought these should both be regarded varieties of ''P. delavayi''. Komarov described ''P. potaninii'' from West Sichuan in 1921, with smaller, deep maroon-red flowers and narrower leaf segments. In 1931 Stern adds ''P. trollioides'' from Northwest Yunnan with yellow flowers shaped like those of ''Trollius'', growing more erect and having larger fruits, which he reduces to ''P. potaninii'' var. ''trollioides'' in 1946, in addition to recognizing ''P. potaninii'', ''P. delavayi'' and ''P. lutea''. In 1953 Stern in cooperation with George Taylor described one more taxon, ''P. lutea'' var. ''ludlowii'', discovered in southeastern Tibet. Fang in 1958 agreed with Stern but ignored ''P. lutea'' var. ''ludlowii''. Wu renamed ''P. potaninii'' to ''P. delavayi'' var. ''angustiloba'' and distinguished ''P. lutea'' from ''P. delavayi'' in 1984. In 1990 Gong recognized ''P. delavayi'', ''P. lutea'', ''P. potaninii'', ''P. potaninii'' var. ''trollioides'', and added ''P. potaninii'' forma ''alba'' with white petals. Pan on the other hand only recognized ''P. delavayi'' including var. ''lutea'' and var. ''angustiloba'', but did not mention ''P. lutea'' var. ''ludlowii''.

Cultural

Crossbreeding of yellow-flowered ''P. delavayi'' with double-flowered ''P. suffruticosa'' by Émile Lemoine has led to the introduction of the color yellow into the cultivated double-flowered tree-peonies. These hybrids are known as the ''P. ×lemoinii''-group, and include double-flowered "Chromatella" , "Alice Harding" and semidouble-flowered "Sang Lorraine" . In 1948 horticultulturist Toichi Itoh from Tokyo used pollen from "Alice Harding" to fertilize the herbaceous ''P. lactiflora'' "Katoden", which resulted in a new category of peonies, the Itoh or intersectional cultivars. These are herbaceous, have leaves like tree peonies, with many large flowers from late spring to early autumn, and good peony wilt resistance. Some of the early Itoh cultivars are "Yellow Crown", "Yellow Dream", "Yellow Emperor" and "Yellow Heaven".