Habitat and distribution – at altitudes around 2000 m, in clearings and margins of deciduous forests and dense deciduous scrub. At present known only from the type locality and its surroundings, but it is possible that plants growing to the east of it as far as Gorgan could belong to the same species (in Flora Iranica Paeonia wittmanniana var. nudicarpa is mentioned as growing in Gorgan, too).
Flowering time – May.
Diagnostic characters. Roots carrot- shaped, attenuate downwards, up to 3 cm in diameter. Stem – green, but at the base and below the lower leaves with some reddish staining, bottom scales glabrous, red. Lower leaves biternate with 9-11 leaflets, distinctly glabrous throughout, at the start of vegetation and until blooming noticeably purplish red, later gradually becoming greenish from the midvein, dark green at very end of vegetation, but still retaining the purplish staining at the edges. Leaflets obovate, shortly acuminate at the apex; in young plants the shape variable – from broadly obovate to even lanceolate, upper leaves triternate, with entire or segmented leaflets. Petioles glabrous, leaves glabrous throughout – on the surface, along the margins and enervation. Flowers solitary and terminal with 5-7 pure white petals. Involucrate bracts – 1-2, leaf-like, at blooming time deep bluish purple with red innervation, sepals – 2, orbicular, brownish green with red innervation and a wide reddish purple margin, rounded at the apex, glabrous. Carpels glabrous with a style less than 1 mm long, stigma pink. Filaments 6-7 mm long, white, staining pinkish at the base or light pinkish throughout, glabrous. Anthers 4-5 mm long, creamy yellow, disk – greenish white to creamy white, flat, 1-2 mm wide.
Chromosome number – unknown.
Type – Ex culturae in horto Jānis Rukšāns, plants from Iran, the eastern end of the Elburz, Mazandaran Province, ENE of Firuzkuh, 35.52 N and 52.57 E, alt. 2000 m, originally collected by J.C. Archibald. Holo: GB (Gothenburg).
Syn.: Paeonia wittmanniana var. nudicarpa sensu Riedl, 1969.
- Ruksans J. “Paeonia archibaldii – a new peony species from Iran.” In: International Rock Gardener, nr 102, June 2018, pp. 3-13.