Apios fortunei Maximowicz (1873: 396–397)

Zhang, Fan, Feng, Si, Zhou, Jianjun, Zhang, Rong, Liu, Linhan, Yang, Chengzi, Yu, Xunlin & Pan, Bo, 2018, Apios chendezhaoana (Fabaceae), an overlooked species and a new combination from China: evidence from morphological and molecular analyses, Phytotaxa 371 (1), pp. 1-16 : 10-13

Apios fortunei Maximowicz (1873: 396–397) .

Type:— CHINA. 1845. A. Fortune 44, Barcode K000262505 (lectotype K! here designated).

Apios taiwaniana Hosokawa (1932: 310) . syn. nov.

Type:— CHINA. Taiwan, 17 July 1931, Hosokawa 3026 (holotype TAI!).

Twining herbs. Root with 1–4 spherical tubers. Stem sparsely hirsute. Leaves pinnately 3–7-foliolate, 10–25 cm, leaflets ovate or rhomboid-ovate, 3–7.5 × 1.5–4 cm, apex acute. Pseudoraceme axillary, 6–26 cm. Calyx shallowly 2-lipped. Corolla yellowish green or light green; wings reflexed, almost half as long as standard, usually with a red purple edge; keels much longer than standard, twisted to one side, and curled into a semicircle. Legume linear, ca. 8 cm long.

Apios fortunei and A. taiwaniana both have narrow petals and a twisted keel, and present very few differences. However, A. taiwaniana is claimed to be a Taiwan endemic ( Sa & Gilbert 2010), while A. fortunei is widespread in E China and Japan. Their morphological differences are minor: A. fortunei has ovate to rhomboid-ovate leaflets and 3–7 flowers per node, while A. taiwaniana has ovate-lanceolate to ovate leaflets, and 3–4 flowers per node ( Sa & Gilbert 2010). Michael Woods annotated Taiwan specimens as A. fortunei , according to labels attached to herbarium specimens. J. Li et al. (2014) also considered that A. taiwaniana is a synonym of A. fortunei . We carefully compared specimens from Taiwan with A. fortunei from the China mainland, and found the shape of leaflets variable, from ovate-lanceolate to rhomboid-ovate, and flowers numbers usually 3–4, but sometimes 5 or more. All the distinct characters claimed by Hosokawa (1932) were within the range of variation of A. fortunei so there is no need to retain A. taiwaniana as a separate species. We therefore treat A. taiwaniana as a synonym of A. fortunei .

Distribution and habitat: — Apios fortunei is distributed in China and Japan. It grows on mountain slopes, usually in moist areas at elevations between 50–1900 m above the sea level.

Phenology: —Flowering from June to August, fruiting from September to October.

Specimens examined:— CHINA. Anhui: Guangde, Baidian Gaoshan, 250 m, 26 July 1959, Anonymous 3194 (PE). Chongqing: Wushan, Luoping, Shaping, 1100 m, 13 August 1964, Hong-Fu Zhou 109761 (PE). Fujian: Yanping, Banyan, 13 June 1925, Xin-Xuan Zhong 3381 (AU). Guangdong: Tuantang, 4 August 1930, Xi-Peng Gao 50730 (PE). Guizhou: 8 July 1930, Jiangying 5693 (PE). Fanjingshan, 1932, Da-Hua Du 33510 (PE). Henan: Qintou Mt., July 1959, Jie Chen 655 (HENU). Hubei: Yingshan, Santan, 500 m, June 1992, Dong-Sheng Lu 156 (HENU). Hunan: Yongshun, Liuxi, Mengdong River, 20 June 1988, Beijing Team 1737 (PE). Jiangsu: Lianyungang, Sucheng, Dazhuyuan, 60 m, 21 August 2011, Zeng-Lai Xu & Bao-Cheng Wu 943 (NAS). Jiangxi: Chongyi, Mixi, Xikengwei, 800 m, 9 June 1965, Min-Xiang Nie 8783 (IBSC). Jing’an, Shijing, 960 m, 1 July 1997, Ce-Ming Tan 971087 (PE). Shanghai: Pudong, Chuanshajiang, 23 August 1958, De-Xian Ye 1577 (HHBG). Sichuan: Youyang, 350 m, 19 July 1984, Shi-Xian Tan 153 (PE). Taiwan: Jiayi, Shizhuo, Alishan, 12 November 1985, Y. Tateishi & H. Hoshi 21514 (TAI). Gaoxiong, Tengzhi, 22 October 1982, H. Ohashi et al. 182089 (TAI). Miaoli, Xiangtianhu, 14 July 1986, M.T. Kao 10268 (TAI). Nantou, Bihu, 5 May 1984, S.F. Huang 1845 (TAI). Nantou, Meifeng Farm, Musya- Santinozyo, 30 July 1939, Masamune, Mori, & Nakamura 2381 (TAI). Nantou, Ren’ai, Wushe, 17 May 1985, M.C. Tsai 32 (TAI). Nantou, Riyuetan, 21 September 1929, Kudo & Sasaki 15604 (TAI). Taizhong, Huanshan, 4 September 1993, K.C. Yang s.n. (TAI). Taizhong, Wuling Farm, 8 October 1986, J.C. Wang et al. 3913 (TAI). Taizhong, Wuling Farm, 4 September 1985, S.F. Huang 3162 (TAI). Zhejiang: Dongtianmu, Wuli Temple, 11 July 1957, Yu-Xian He 24867 (NAS). Longquan, Chengbei, Huanghe, Yangwu, 26 June 1972, Medicinal Plants Team 1070 (ZM). JAPAN. Shimotsuke: Tochigi, Hondo, 6 August 1980, Miyoshi Furuse 14337 (PE).

Woods (1988) and Ren (2005) both came to similar conclusions as those above in their dissertations, but they did not publish their results. We therefore recognize four Apios species in Asia, i.e., A. carnea , A. chendezhaoana , A. fortunei , and A. delavayi . Three varieties of A. delavayi are recognized as well, i.e., var. dalavayi , var. gracillima , and var. pteridietorum . A morphological comparison between them is provided in Table 2.

Key to Apios species: Figure 5

1. Tubers usually undeveloped; corolla red, reddish purple or orange; standard flat, fully open when flowering .................. A. carnea

1. Roots starchy and tuberous; corolla white, pale yellow, greenish white, maroon, pink, or purple; standard in a pocket shape, incompletely open when flowering..............................................................................................................................................................2

2. Terminal leaflets broad triangular........................................................................................................................... A. chendezhaoana

2. Terminal leaflets lanceolate, ovate or rhomboid ovate.......................................................................................................................3

3. Leaflets ovate to rhomboid ovate; upper half of keel twisted to one side.......................................................................... A. fortunei

3. Leaflets ovate to lanceolate; keel curved but not twisted...................................................................................................................4

4. Inflorescences with lax flowers; corolla pale yellow, greenish white, light purple, or dark purple; plant of SW China...................5

4. Inflorescences with densely congested flowers; corolla maroon or pink; plant of N America..........................................................7

5. Flowers pale yellow or greenish white, plant of Sichuan and Yunnan, east of the Mekong-Salween Divide ..................................... ...................................................................................................................................................................... A. delavayi var. delavayi

5. Flowers purple, plant of NE India, Xizang and Yunnan.....................................................................................................................6

6. Leaflets lanceolate to ovate, apex acute to acuminate; inflorescence 6–30 flowered; plant of Assam ( India), SE Xizang and NW Yunnan ( China), west of the Mekong-Salween Divide ........................................................................ A. delavayi var. pteridietorum

6. Leaflets linear to narrow lanceolate, apex acute to rounded; inflorescence 2–4 flowered; plant of Central and SE Yunnan .............. ................................................................................................................................................................... A. delavayi var. gracillima

7. Corolla maroon; standard with a short prolongation (1.5–2 mm) at the tip .................................................................. A. americana

7. Corolla pink; standard with a long prolongation (6–8 mm) at the tip ............................................................................... A. priceana

Figures

FIGURE 5. Floral comparison of Apios species: (A) A. carnea from Hunan, China, courtesy of Lei Wu; (B) A. fortunei from Hunan, China, photographed by Fan Zhang; (C) A. delvavayi var. delavayi from Sichuan, China, courtesy of Ang Liu; (D–E) A. delavayi var. pteridietorum. (D) from Chayu, Xizang, China, courtesy of Chun-Mei He. (E) from Gongshan, Yunnan, China, courtesy of Bin Chen; (F) A. americana, from Washington, United States, courtesy of Adam J. Peterson; (G) A. priceana, from Maryland, United States, courtesy of Alan Cressler.