Hong De-yuan1, Pan Kai-yu1 & Pei Yan-long2

The identity of Paeonia decomposita Hand.-Mazz.

TAXON 45 - FEBRUARY 1996 pp. 67-69

1 Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100093, China.

2 Institute of Crops, Chinese Academy of Agricultural Sciences. Baishiqiao Road 30, Beijing 100081, China.

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Summary

Hong, D.-Y., Pan, K.-Y. & Pei, Y.-L.: The identity of Paeonia decomposita Hand.-Mazz. -Taxon 45: 67-69. 1996. - ISSN 0040-0262.


Paeonia decomposita, which has been ignored or considered synonymous with P. suffruticosa. is shown to be an earlier name for P. szechuanica. A detailed description is provided of this beautiful woody peony only known from a small area in N.W. Sichuan. China.


Introduction

Paeonia decomposita was described in 1939 by Handel-Mazzetti on the basis of the specimen H. Smith 4641 from Chosodjo, N.W. Sichuan, China. Stern (1946: 142) considered it conspecific with P. suffruticosa Andr., stating: "I have seen a photograph of the type specimen (H. Smith, No. 4641) of P. decomposita .... and if this photograph is compared with Rock's specimen of P. suffruticosa in the Kew Herbarium they will be found to be alike". Rock's specimen of P. suffruticosa was since described as a new subspecies, P. suffruticosa subsp. rockii S. W. Haw & Lauener (1990), which has been raised to specific level, P. rockii (S. G. Haw & Lauener) T. Hong & J. J. Li (in T. Hong & al., 1992). In his revision of Chinese peonies. Fang (1958: 302, 314-315) stated, under P. suffruticosa, that P. decomposita was an imperfectly known species, which he treated as a doubtful synonym of P. suffruticosa in the English abstract. In the same paper he described a new woody species, P. szechuanica Fang, also from N.W. Sichuan. Pan (1979: 41) treated P. decomposita as a straightforward synonym of P. suffruticosa and recognized P. szechuanica as a correct name. H.-Y. Hong (in Fu 1992: 536-537) included P. szechuanica as an endangered species. Osti (1994) also used the name P. szechuanica, ignoring P. decomposita. Therefore, P. decomposita has not again been recognized as a correct name since its publication.


Taxonomy

Examination of the holotype of Paeonia decomposita shows that, contrary to Stem's (1946) opinion, it differs specifically from P. suffruticosa, including Rock's specimen (P. rockii). It is easily distinguished from both P. suffruticosa and P. rockii by its leaves that are compound 3-4 times, with (29)33-63 leaflets; its rose petals, a white disc, and glabrous carpels, as shown in the following key.


1.

Carpels glabrous; petals rose; disc white; leaflets (29)33-63, glabrous on both surfaces ...... P. decomposita

 

Carpels tomentose; petals white, with or without a dark-purple blotch at the base; disc yellowish white or purple; leaflets 9 or 19-29, hairy along the veins underneath ... 2

2.

Petals entirely white; disc purple; leaflets 9 ................. P. suffruticosa

 

Petals with a dark-purple blotch at the base; disc yellowish white; leaflets 19-29 ... P. rockii


To our knowledge, the wild form of Paeonia suffruticosa is confined to S.W. Shanxi Province and Shaanxi Province, and P. rockii only occurs in S.E. Gansu, S. Shaanxi, W. Henan and W. Hubei. Neither species is found in Sichuan Province. Fang's P. szechuanica is conspecific with P. decomposita and the former name should be treated as a synonym of the latter.


Paeonia decomposita Hand.-Mazz. in Acta Hort. Gothob. 13: 39. 1939. - Type: China, N. W. Sichuan.Chosodjo (Chuosijia), 18 Oct 1922, H. Smith 4641 (UPS; Fig. IA). = Paeonia szechuanica Fang in Acta Phytotax. Sin. 7: 315. 1958. - Type: China, N. W. Sichuan. Barkam, 29 Apr 1957, U Xin (H. Lee) 70316 (SZ, Fig. 1B; isotype: PE).

Deciduous shrub 50-150 cm, glabrous throughout; branches terete; bark grey-black. flakily peeling off; young shoots purple-red, with persistent scales at the base. Leaves alternate, usually the second from below best developed and with most leaflets, ranging from (29)33 to 63, mostly three or rarely four times compound, the first and third division triple, the second pinnate; petiole 3.5-8 cm; lamina deltoid-ovate in outline, 15-22 cm x 10-20 cm, dark green above, pale green below; terminal leaflets elliptic or ovate, 2.5-6.5 cm x 1.2-3 cm, 3-partite to the base or 3-fid, the terminal segments 3-lobed, lobes elliptic, narrowly elliptic or ovate-lanceolate, 0.8-5.3 cm x 0.3-1.5 cm, pedolules 1-1.5 cm; lateral leaflets elliptic, 1.8-4.4 cm x 0.6-2.5 cm, 3-lobed or coarsely toothed, petiolules 0.1-0.5 cm. Rowers terminal, 10-15 cm in diameter. Bracts 2-3(-5), unequal in size, linear-lanceolate. Sepals 3(-5), broadly obovate, mucronate at the tip, green, 2.5 cm x 1.5-2.0 cm. Petals 9-12, rose, obovate, usually 2-lobed and irregularly incised or toothed at the apex, 4 - 7 cm x 3 - 5 cm. Disc white, papery, enveloping 1/2-2/3 of the carpels, with triangular teeth. Carpels mostly 5, very rarely 4 or 6, glabrous; style short, stigma flattened, recurved. Follicles green-brown when young, black-brown when mature, ellipsoidal, 2-3 cm, with. 1-3 seeds. Mature seeds back, shiny, spheroidal or broadly ellipsoidal, 8-10 mm long, 6-8 mm in diameter. 2n = 10 (Hong & al., 1988).

Found so far only in a small area in N.W. Sichuan Province, China (31°15' to 31°54'N; 101°42' to 102°12'E), growing in loose thickets of spiny shrubs at altitudes of 2300-3100 m. Flowering from late April to early June. Not so far introduced into cultivation.

Specimens examined. - Sichuan (north-west): Chosodjo (Chuosijia), ad radices rupium, c. 3000 m, 18 Oct 1922, H. Smith 4641 (UPS); Barkam, 2650 m, 29 Apr 1957, Li Xin 70316 (PE, SZ); Barkam, 3100 m, 10 Jun 1957, Li Xin 71387 (PE, SZ); Barkam, 2700 m, 11 May 1957, Li Xin 70647 (PE, SZ); Barkam, 2750 m, 19 May 1957, Li Xin 71071 (PE, SZ); Barkam, 2750 m, 15 May 1985, Hong De-yuan & Zhu Xiang-yu PB 85045 (PE); Barkam, 2650 m, 8-16 Aug 1991, Pei Van-long 9114 (PE); Barkam, Zonggang, 2650 m, 11 May 1957, Li Xin 70591 (PE, SZ); Barkam, Zong-gang, 2640 m, 18 May 1957, Li Xin 70701 (PE, SZ); Barkam. Zonggang, 2620 m, 13 May 1985, Hong De-yuan & Zhu Xiang-yu PB 85025 (PE); Jinchuan (Dajing), Ma'erbang, Liu Jiagou, 13 May 1958, Li Xin 77098 (PE, SZ); Jinchuan. Sa'er Township, 2300 m, 8-16 Aug 1991, Pei Van-long 9113 (PE).


Fig. 1.

A, holotype of Paeonia decomposita;

B, holotype of P. szechuanica.


 



Acknowledgements

Support by the Special Foundation of Taxonomy and Floristics of the Chinese Academy of Sciences is gratefully acknowledged. The authors are grateful to the curator of the Botanical Museum, Uppsala University, Sweden, for kindly sending the type specimen of Paeonia decomposita, on loan, and to Professor Xu Jie-mei at Sichuan United University for making the photograph of the type specimen of P. szechuanica available.


Literature cited

Fang.W.-P. 1958. Notes on Chinese peonies. Acta Phytotax. Sin. 1: 297-327.

Fu, L.-K. (ed.), 1992. China plant red data book, 1. Beijing.

Haw, S. G. & Lauener, L. A. 1990. A review of infraspecific taxa of Paeonia suffruticosa Andrews. Edinburgh J. Bot. 47: 273-281.

Hong, D.-Y., Zhang, Z.-X. & Zhu, Z.-Y. 1988. Studies on the genus Paeonia (I): report of karyotypes of some wild species in China. Acta Phytotax. Sin. 26: 33-43.

Hong, T.. Zhang, J.-X., Li, J.-J., Zhao, W.-Z. & Li, M.-R. 1992. Study on Chinese wild woody peonies I: new taxa of Paeonia L. sect. Moutan DC. Bull. Bot. Res. (Harbin) 12: 223- 236.

Osti, G. L. 1994. The tree peonies revisited. New Plantsman 1: 195-206.

Pan, K.-Y. 1979. Paeonia. Pp. 37-59 in: Wang, W.-T. (ed.). Flora reipublicae popularis sinicae, 27. Beijing.

Stern, F. C. 1946. A study on the genus Paeonia. London.