Arum erubescens Wallich, Pl. Asiat. Rar. 2: 30. 1831; Arisaema alienatum Schott var. formosanum Hayata; A. biradiatifoliatum Kitamura; A. brevipes Engler; A. consanguineum Schott; A. consanguineum subsp. kelung-insulare (Hayata) Gusman; A. erubescens var. consanguineum (Schott) Engler; A. formosanum (Hayata) Hayata; A. formosanum var. bicolorifolium T. C. Huang; A. formosanum f. stenophyllum Hayata; A. fraternum Schott; A. hypoglaucum Craib; A. kelung-insulare Hayata; A. kerrii Craib (1912); A. kerrii Gagnepain (1941); A. linearifolium J. T. Yin & Gusman; A. oblanceolatum Kitamura; A. tatarinowii Schott; A. undulatum K. Krause; A. vituperatum Schott.

Tuber depressed globose, 2-7 cm in diam. Cataphylls 3, dark green, with whitish striae or spots, to 55 cm, acute at apex. Petiole and peduncle green, smooth, unmarked. Leaf solitary, occasionally 2; petiole to 100 × ca. 2 cm, proximal ca. 50 cm sheathing into pseudostem; leaf blade radiate; leaflets 18-23, sessile, green abaxially, dull green adaxially, narrowly elliptic or narrowly linear, 16-28 cm × 2-20 mm, base cuneate, apex long acuminate and caudate, with filiform tail 7-10 cm; veins raised abaxially, impressed adaxially; lateral veins numerous, obliquely ascending. Peduncle shorter than petioles, to 75 cm, free part ca. 9 cm. Spathe green, with indistinct whitish stripes or not; tube cylindric, 6-7 × ca. 1.5 cm, auriculate and recurved at throat; limb deep green sometimes with purple margin outside, pale green inside, triangular-ovate, 8-12 × 4-8 cm, apex acuminate with long purple filiform tail, arching; tail to 35 cm, pendulous. Spadix unisexual; female zone conic, ca. 3.5 × 1.5 cm; ovary green, obovoid; stigma sessile, spherical, pilose; male zone cylindric, 4-4.5 cm × 4-5 mm; synandria dark violet; anthers subsessile, 2 or 3, dehiscent by apical pores. Appendix pale green, cylindric or narrowly conic, ca. 7 cm × 2-4 mm, with some acute neuter flowers at base. Infructescence nodding. Berries red. Fl. Jun-Jul.

H. Hara (Bull. Univ. Mus. Univ. Tokyo 2: 321-354. 1971) noted that Arisaema consanguineum is characterized by having a threadlike appendage at the apex of the leaflets and spathe (but sometimes absent), a sessile spadix appendage with neuter flowers at least in the female spadix, and a nodding infructescence, whereas A. erubescens lacks a threadlike appendage on the leaflets and spathe, has a stipitate spadix appendage without neuter flowers, and has an upright infructescence. In the present treatment, we follow many Chinese floras in recognizing a wide range of variation for Chinese A. erubescens including both types of plants. One of us (Murata), until recently, considered that only true A. consanguineum is distributed in China, but he found the second type of plants, which share some characteristics with A. erubescens, north of Kunming City. However, these plants have a threadlike appendage on the leaflets and spathe and do not fit true A. erubescens (nor A. consanguineum in the strict sense) and could represent a new species. A revision of the whole A. erubescens-A. consanguineum group is now required.

Pinus forests, mixed forests, thickets, grassy slopes, lakesides, between rocks; below 3200 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Bhutan, NE India, Laos, Myanmar, Nepal, N Thailand, Vietnam].