Paeonia daurica((Hong, De-Yuan. “Peonies of the World. Taxonomy and phytogeography.” Kew: Royal Botanic Gardens, 2010, pp. 168-176.))
Perennials. Roots carrot—shaped, attenuate downwards, up to 4.6 cm in diameter. Lower leaves biternate with 9 leaflets, occasionally 1-2 leaﬂets segmented, and thus leaflets/leaf segments usually 9, rarely 10 or 11, in number, entire, broad—obovate, oblong, rarely wide—elliptic, sometimes undulate, truncate or rounded, rarely acute or even short—acuminate at the apex, 8—17 cm long, 4.8—11.5 cm wide, glabrous above, glabrous or sparsely to densely villose, or sparsely to rather densely puberulous beneath. Flowers solitary and terminal; involucrate bracts 0—2 in number, leaf-like; sepals mostly 3, less frequently 2 in number, green but with purple periphery or entirely purple, orbicular or ovate—orbicular, up to 3.5 cm long, all rounded at the apex; petals 5—8 in number, usually red or rose, less frequently yellow, pale yellow, white, or yellow but with a red spot at the base or with red periphery; filaments purple; disk c. 1 mm high, waved, tomentose above; carpels 1-5 but mostly 2 or 3 in number, mostly tomentose, less frequently glabrous, hairs 2.5-3 mm long; stigmas nearly sessile, red, 1.5—2 mm wide.
Chromosome number: 2n = 10 and 20 (see each subspecies for detail).
Three lowland subspecies, subsp. daurica, subsp. coriifolia and subsp. mlokosewitschii are diploid, whereas three alpine or subalpine subspecies, subsp. macrophylla, subsp. tomentosa and subsp. wittmanniana are tetraploids. No chromosome information is yet available for subsp. velebitensis.
Growing in deciduous broad—leaved or mixed forests, or at the edges of forests, on various media and at altitudes from 350 to 2,740 m. Widely distributed from Croatia in the west to N Iran in the east via Turkey and the Caucasus. Within the range of this species, the populations in the Caucasus (including the Transcaucasus), the Talish Mountains and the Elburz Mountains are diverse and polytypical, both in morphology and chromosome number. They have been treated as ﬁve allopatric subspecies with subsp. coriifolia (diploid) in the lowlands of Georgia, subsp. mlokosewitschii (diploid) in E Georgia, NW Azerbaijan and Dagestan in Russia, subsp. wittmanniana (tetraploid) in the highlands of Abchasia (Georgia) and adjacent regions, subsp. macrophylla (tetraploid) in the western Transcaucasus (Armenia, Georgia and NE Turkey), and subsp. tomentosa (tetraploid) in the Talish Mountains (Azerbaijan and Iran) and the Elburz Mountains (Iran) (Hong & Zhou, 2003)
In Paeonia daurica, the number of leaﬂets/ leaf segments of lower leaves is mostly 9, rarely 10, very occasionally 11, whereas in P. mascula this ranges from 11 to 22, rarely 10, very occasionally 9. This character is rather stable within populations. ln the population D. Y. Hong et al. H02215 (Mt Amanos, Hatay, Turkey), for example, we observed 37 individuals that all had 9 leaﬂets/leaf segments. On this mountain, there were hundreds of P. daurica individuals at altitudes from 1,300 to 1,550 m, but very few of them had more than 9 leaﬂets/leaf segments. The length of the terminal leaﬂets varied from 5.5 to 15.2 cm (9.2 ± 1.9 cm) in P. daurica, compared with 7.7—16.7 cm (11.8 ± 2.5 cm) in P. mascula. The ratio of the length to width ranged from 1.01 to 1.82 (1.45 ± 0.23) in P. daurica, and from 1.33 to 2.18 (1.79 ± 0.22) in P. mascula. The apex of terminal leaﬂets was mostly truncate, broad- rounded or rounded in P. daurica, but mostly acute, cuspidate or rounded—cuspidate in P. mascula. The widest point of the terminal leaﬂets also differed between the two species. Although the widest point was above the middle of the terminal leaﬂets in both entities, it was much above the middle, about halfway between the top and the middle in P. daurica, but not much above the middle in P. mascula. Thus, the terminal leaﬂets were broad-obovate or nearly orbicular in P. daurica, but obovate, oblong or ovate in P. mascula. As indicated by Hong et al. (2006), P. daurica was clearly, though not distantly, differentiated from P. mascula in morphology. They were not intermingled with each other, even in S Turkey where the two entities were sympatric. Morphologically, they differed in number of leaﬂets/ leaf segments of lower leaves, and also in the shape of the terminal leaﬂets. The great majority of individuals of these two species could be distinguished.
Stearn and Davis (1984) stated that P. daurica (= P. mascula subsp. triternata) and P. mascula geographically overlapped in the eastern Aegean islands (Lesvos and Samos), and that they showed some morphological overlap in Anatolia. We critically examined all the specimens of this group from the regions mentioned above at the herbaria ATH, E, G, LD and UPA, but found that the specimens from Lesvos and Samos, including E. Stamatiadou 2666 (ATH) determined by P. H. Davis as P. mascula subsp. triternata, all belonged to P. mascula subsp. mascula. Thus, no subsp. triternata was present on these two islands. In Anatolia, subsp. triternata and subsp. mascula did coexist in some areas, e.g. in Hatay Province, Turkey, but they were not found to overlap morphologically. Instead, they were rather distinct. Their morphological differentiation can be easily understood when their difference in chromosome number is considered. No hybrids between them have been discovered.
Seven subspecies are recognised and keyed out below.
Paeonia daurica subsp mlokosewitschii
Chromosome number: 2n= 10
Growing in deciduous forests dominated by Fagus, Quercus, Ulmus, Castanea and Acer, at an altitude of 960—1,060 m. To date, found only in E Georgia, NW Azerbaijan and Dagestan in Russia.
The type specimens of Paeonia mlokosewitschii and P. lagodechiana both came from the same population, which we visited and observed during our expedition in 1999. This population (D. Y. Hong & S. L. Zhou H99035) was extremely polymorphic in petal colour and leaﬂet indumentum.
Among the seven subspecies of Paeonia daurica, subsp. mlokosewitschii is relatively distinct; its leaflets are usually obovate, rounded and mucronate at the apex, and mostly sparsely or rather densely puberulous but sometimes glabrous beneath. Saunders and Stebbins (1938) made a cross between Paeonia triternata from SE Europe (= P. daurica subsp. daurica) and this entity, which showed that they were interfertile. This suggests that P. mlokosewitschii might be better treated as a subspecies within P. daurica.