Paeonia anomala is a non-woody species of peony ½–1 m high, with an irregular carrot-shaped taproot over ½ m long and 2 cm thick, gradually getting thinner downwards with slender side roots. Like all
diploid peonies, it has 10 chromosomes (2n=10).
Leaves and stems The leaves have no sheath or
stipules and are alternately arranged along the stem, are divided into a
leaf stalk and
leaf blade. The leaf blade is twice compounded or very deeply incised, first into three leaflets, themselves palmately compounded or deeply divided (this is called biternate), each leaflet being further divided into segments that themselves are lobed, resulting in seventy to one hundred segments of ¾–3¼ cm wide. At the end of the growing season the leaves may turn vivid red.
Inflorescence One or very rarely two hermaphrodite flowers fully develop on each stem, while one or two flowerbuds are arrested in their development, and two to five leaflike
bracts are present. The flowers are somewhat nodding. Each flower has three to five leathery
sepals that mostly end in a stretched tip, making it "leafy", but sometimes one and rarely two sepals may be obovate with a rounded tip, which do not fall after flowering. The corolla usually consists of six to nine oblong
cyclamen or rarely pink to white
petals of 3–6½ × 1½–3 cm. Towards the centre of the flower are many
stamens consisting of filaments of ½–1 cm topped with anthers that ripen from the inside out, open with slits and release yellow pollen. The pollen is released in sets of four grains together. Dependent on latitude and altitude flowers open between April and July and are said to smell like
lily of the valley. Petals and stamens are shed after flowering. The two to five carpels are initially pale yellow with reddish
stigmas, but eventually become green, may be hairless or covered in soft felty hairs. Within, several large, initially red but eventually shiny black seeds of 6×4 mm develop, and each carpel opens by a slit over the entire length. Ripe seedheads may be present during August and September.
Differences with related species Few other peony species are non-woody and have finely segmented leaves.
Paeonia tenuifolia has even more divided leaves with narrowed segments of up to 6 mm wide, the basal leaves consisting of more than one hundred and thirty segments.
Paeonia emodi has about 15 entire segments per basal leaf.
P. anomala however strongly resembles
Paeonia intermedia, from which it can be distinguished because the latter has many spindle-shaped roots and at least the two innermost sepals are rounded. Even more morphologically alike is
Paeonia veitchii which differs only from this species because it usually has two to four flowers per stem in addition to two undeveloped buds, rather than only one flower, rarely two, in addition to few undeveloped buds. ==Taxonomy==