Paeonia algeriensis

Stems are 7–10 mm (0.28–0.39 in) in diameter. The leaves near the base of the stem consist of three sets of three leaflets, some of which are deeply incised, resulting in ten to thirteen leaflets and leaflet segments. These are oval in shape, with a round or slightly wedge-shaped foot, an entire margin and a pointed tip, 9–18 cm (3.5–7.1 in) long and 5½-8½ cm (2.17–3.35 in) wide. The leaflet stalks and the underside of the leaflets are always softly hairy, sometimes so dense as to giving it a whitish appearance.[2]

Each stem only carries one flower at the tip. Each flower may be subtended by one leaflet-like bract, but this may also be absent. There are three or four hairless, roundish, 2½–3 × 2-2½ cm (0.98–1.18 × 0.79–0.98 in) sepals which are all rounded at their tip, tinged purple inside and around the margin. The pink to cyclamen-colored inverted egg-shaped petals are 5–6 cm (2.0–2.4 in) long and 3–4 cm (1.2–1.6 in) wide and are rounded at their tip. Like in all peonies there are many stamens. A very short, about 1 mm (0.039 in) and slightly wavy disk surrounds the base of one or two carpels, which are hairless or have few scattered hairs. They are topped by a 1–3 mm (0.039–0.118 in) long style that end in red stigmas. The carpels develop into column-like follicles of 4-5½ cm (1.57–2.17 in) long, that contain oval, 7×9 mm (0.28×0.35 in), black seeds.[2]

Paeonia algeriensis has one or two large, almost always entirely hairless carpels of about 5 cm (2.0 in) long when ripe, and the ten to thirteen leaflet segments are covered in felty hair underneath and each 9–18 cm (3.5–7.1 in) long and 5½–9½ cm (2.17–3.74 in) wide. The combination of these characters is unique. Statistically, carpel size and number, and leaflet size are also in their own right can be used to distinguish this species. Paeonia mascula, which occurs over a large area in areas bordering the Mediterranean in Asia and Europe, most often has three or four smaller felty carpels, although some flowers only have one or two and others as much as five, and leaflet are smaller and usually bold underneath. Paeonia coriacea from southern Spain and Morocco has leaflets hairless or sparsely haired undersides and each 5–15 cm (2.0–5.9 in) long and 2–8 cm (0.79–3.15 in) wide, mostly two and sometimes one carpel per flower, which develop into follicles of 3½–4¾ cm (1.38–1.77 in). Paeonia corsica, from Corsica, Sardina and western Greece mostly has only nine, smaller leaflets of 4–13 cm (1.6–5.1 in) long and 2–8 cm (0.79–3.15 in) wide, and three to five (occasionally two) usually softly haired carpels, which develop into follicles.[2]