A New Species of Asarum (Aristolochiaceae) from China Yong Wang, Qing-Feng Wang, Wahiti Robert Gituru, and You-Hao Guo Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China. [email protected]; [email protected] (for correspondence); [email protected]; [email protected] ABSTRACT. A new species of Asarum L., A. cam- mm long, with thick ¯eshy adventitious roots clus- pani¯orum Wang Yong & Wang Q. F. (Aristolochi- tered at nodes. Leaves 2 or 3 on one branchlet, with aceae), is described from Hubei Province, China. petiole 10±30 cm long, the cataphylls at its base It belongs to Asarum sect. Heterotropa (Morren & ovate, up to 2.5 cm long, densely ciliate, shed when Decaisne) Braun and is readily distinguishable in leaves fully grown, blade triangular or oblong-ovate, having simple bell-shaped ¯owers and little orna- membranous, 7±20 3 5±14 cm, acute or acuminate mentation of the calyx. A chromosome count of 2n at apex, auriculate at base, base of the sinus 1±1.5 5 26 is recorded. cm wide, sparsely pubescent above, with or without Key words: Aristolochiaceae, Asarum, China. white blotches along midvein above, glabrous be- low, margins mucronate as extensions of secondary Asarum L. s.l. is a north temperate genus whose veins. Flowers solitary, facing downward, pale pur- center of distribution is eastern Asia. According to plish green, large, ca. 3 cm across, 3.5 cm long, the classi®cation system proposed by Cheng and peduncle 4±6 cm long; perianth tube campanulate, Yang (1983), which has been accepted by previous with the lower portion broadly cylindrical, ca. 1.3 researchers (Kelly, 1997, 1998), the section Het- cm long, 1.0 cm diam., internally pale yellow-green erotropa consists of ca. 50 species that are char- and with ca. 30 longitudinal smooth ribs, with the acterized by perianth tubes of various shapes, ori- upper portion abruptly swollen into a broad bell- ®ce rings usually present but sometimes absent, shaped tube, ca. 1.0 cm long, 3 cm diam., inter- and stamens subsessile or with very short ®laments nally glabrous and pale yellow-green, not constrict- (Cheng & Yang, 1983). During ¯oristic investiga- ed, without ori®ce, the connecting part between tion of Jiugongshan Nature Reserve located in upper portion and lower portion ¯at, internally dark southeastern Hubei Province, China, we encoun- purple, having smooth longitudinal ribs continuous tered a new species of Asarum with strikingly large with those on the internal tube surface of the lower bell-shaped ¯owers whose distinct perianth tube portion, perianth lobes broadly triangular-ovate, ca. and subsessile stamens indicate its taxonomic placement in section Heterotropa. We describe this 1 3 2.5 cm, nearly erect, having a dark purplish species on the basis of fresh and live material. A crescent toward the middle, triangular, pale yellow- few individuals of this new species are in cultiva- green beneath and continuous with internal tube tion at the botanical garden of the Chinese Botan- surface, stamens 12, ®laments very short, anthers ical Institute of Wuhan. These plants have been 4 mm long, with connective obtuse, ovary half-in- previously identi®ed as A. insigne Diels (Lin et al., ferior, styles 6, ca. 7 mm long, with bi®d apices, 1995), probably due to the similarities of ¯oral mor- the stigma oblong-ovoid, inserted in apex notch, phologies between the two species. ovary subglobose, ca. 1.5 cm long, 1.7 cm diam., seeds ovate, dark brown, concave on one side, pro- Asarum campani¯orum Wang Yong & Wang Q. truding on opposite side, ca. 4 mm long, 2.5 mm F., sp. nov. TYPE: China. Hubei: Jiugongshan wide. Chromosome number 2n 5 26. Nature Reserve, bamboo bush on slope, yellow sandy soil, 400 m, 23 July 1998, Wang Yong Distribution and habitat. Asarum campani¯o- 2390 (holotype, PE; isotype, WH). Figure 1. rum is endemic to a low mountainous area in south- eastern Hubei Province in central China. It occurs Haec species quoad ¯ores magnos atque perianthii tub- um campaniformem intus longitudinaliter crasse plicatum under dense brush dominated by the bamboo spe- A. maximi et A. insignis similis, sed ab eis perianthii lob- cies Phyllostachys nidularia Munro. The habitats ulis suberectis atque tubo intus non papillato-rugoso dif- are shaded and moist throughout the year. There fert. are villages and farms scattered around. We sup- Perennial herb; rhizomes short, internodes 5±15 pose that both special ecological requirements and NOVON 14: 239±241. 2004. 240 Novon Figure 1. Asarum campani¯orum Wang Yong & Wang Q. F. ÐA. Habit. ÐB. Leaf blade. ÐC. Longitudinal section of ¯ower. ÐD. Styles and stamens, showing longitudinal section of ovary. ÐE. Seeds, appearance from different views. Drawn from the type gathering, Wang Yong 2390 (PE). Volume 14, Number 2 Wang et al. 241 2004 Asarum campani¯orum (Aristolochiaceae) disturbance by human activities contribute to the forming three semicircular pulvinate areas basal to rarity of this species in nature. the lobes. These pulvinate areas in the ¯owers of Species in Asarum sect. Heterotropa have diverse A. maximum and A. insigne are white or pinkish, modi®cations of their ¯owers, for example, contrast- strongly contrasting in color to the dark velvet mar- ing colors of the perianth lobes, constriction or di- gins of the perianth lobes and the central portion lation of calyx ornamentation or surface sculpturing of the ¯owers. In addition, the ¯owers of these two such as tubercles, pulvinus, ori®ce rings, and lon- species tilt upward, making the ¯owers easily seen gitudinal or reticulate ridges (Kelly, 1997, 1998; by observers. Sugawara, 1988). In comparison to other species in A chromosome count of 2n 5 26 was obtained section Heterotropa, the ¯owers of Asarum campan- for Asarum campani¯orum, using the methodology i¯orum are more simpli®ed. They have large peri- of Sugawara and Ogisu (1992), from fresh root tips. anth tubes with the perianth lobes short and re- Sugawara and Ogisu (1992) revealed that A. max- duced. The calyces are smooth without constriction imum shared a chromosome number of 2n 5 26 or ori®ce rings, and papillate, pulvinate or dilated (the chromosome number of A. insigne is still un- areas are absent. Only parallel longitudinal ridges known). These results contradict the earlier sug- are present at the base of the perianth inner sur- gestions that the chromosome number 2n 5 24 is face. The ¯ower color of A. campani¯orum is ba- characteristic in Heterotropa (Sugawara, 1981; Yin- sically pale purplish green, and no strongly color- ger, 1983; Kelly, 1997). Further investigations are contrasting area is present. The ¯owers face needed to improve our knowledge. downward throughout anthesis and thus the inner Paratypes. CHINA. Hubei: Tongshan County, Gaohu parts of the ¯owers cannot easily be seen by an Village, 350 m, 5 July 1998, Wang Yong 2877 (WH); 2 observer in the ®eld. Among the species of section km along the road from Gaohu Village to Jiugongshan Town, 450 m, 24 Mar. 1989, Ye Qigang & Chen Shusen Heterotropa, Asarum sagittarioides C. F. Liang is 5476 (WHBI). similar to A. campani¯orum in vegetative morphol- ogy. Both species are robust perennials with a pair Acknowledgments. The authors thank A. Mich- of large membranous leaves in each branchlet, a ele Funston at MO for her advice and encourage- thick cluster of ¯eshy adventitious roots, leaf mar- ment, and for reading drafts of the manuscript. The gins mucronate as extensions of secondary veins, project was supported by the ``State Key Basic Re- and an auriculate leaf base with a wide sinus. How- search and Development Plan of China (973)'' (Pro- ever, ¯owers in A. sagittarioides differ from those ject No. G2000046805). of A. campani¯orum by their deeply constricted Literature Cited perianth tubes with conspicuous ori®ce rings at the Cheng, C. Y. & C. S. Yang. 1983. A synopsis of the Chi- throat and perianth lobes with prominent papillae nese species of Asarum (Aristolochiaceae). J. Arnold at their base. Asarum wulingenses C. F. Liang and Arbor. 64: 565±597. A. longerhizomatosum C. F. Liang & C. S. Yang are & . 1988. Asarum. In: H. S. Kiu & Y. R. Ling (editors), Flora Reipublicae Popularis Sinicae, To- the closely allied species of A. sagittarioides, but mus 24. Science Press, Beijing. they differ from A. campani¯orum in having smaller Kelly, L. M. 1997. A cladistic analysis of Asarum (Aris- (7±17 3 5±9 cm in A. wulingenses, 8±14 3 5±8 tolochiaceae) and implications for the evolution of her- cm in A. longerhizomatosum) chartaceous leaves kogamy. Amer. J. Bot. 84: 1752±1765. 1998. Phylogenetic relationship in Asarum (Ar- with narrower sinuses (rounded to cuneate in A. istolochiaceae) based on morphology and ITS sequenc- longerhizomatosum, cuneate in A. wulingenses)at es. Amer. J. Bot. 85: 1454±1467. leaf base and gradually enlarged perianth tubes Liang, C. F. 1975. The Aristolochiaceae of Kwangsi ¯ora. with ori®ce rings at the throats (Cheng & Yang, Guihaiya 13(2): 10±23. Lin G., N. Kang & Q. H. Liu. 1995. A study on intro- 1988; Liang, 1975). duction and cultivation of Asarum in Hubei. J. Wuhan Two other species in Asarum sect. Heterotropa, Bot. Res. 13(2): 172±176. A. maximum Hemsley and A. insigne, appear to be Sugawara, T. 1981. Taxonomic studies of Asarum sensu closely allied to A. campani¯orum. The ¯oral mor- lato I. Karyotype and C-banding pattern in Asarum s. str., Asiasarum and Heterotropa. Bot. Mag. 94: 225±238. phologies of these three species are similar in hav- . 1988. Floral biology of Heterotropa tamaensis ing numerous (ca.