Arisaema vexillatum H.Hara & H.Ohashi

Plants dioecious. Tuber brown outside, white inside, depressed globose, 1.5–3cm in diam. Cataphylls 2 or 3, pink to purple, to 8cm, membranous. Leaf solitary; petiole greenish, not spotted, terete, 15–18cm, basal part forming pseudostem, smooth, not verrucose; leaf blade 3-foliolate; leaflets subsessile, green usually with bluish margins; central leaflet broadly obovate or rhombic, 4–5(–11) × 4–5(–10.5)cm, apex abruptly acuminate or rounded with an acumen 2–3mm; lateral leaflets larger than central one, ovate or rhombic, 8–9(–15) × 4(–9)cm, base cuneate, slightly oblique, apex acuminate. Peduncle greenish as petiole, shorter than petioles, 6–10cm. Spathe tube dark purple with whitish longitudinal lines, cylindric, 4.5–5 × 1.5–2cm, throat obliquely truncate, slightly recurved, not auriculate, inside distinctly lamellate, throat abruptly constricted into an intermediate zone 1.5–2cm wide; limb above intermediate zone strongly dilated, reniform or subcordate, 3–5 × 4–7cm, purple with whitish reticulate networks, apex rounded with a tubular tail 3–4cm. Spadix unisexual; female zone conic, ca. 1.2cm × 8mm; ovary green; stigma subsessile, dark purple, ovoid; male zone cylindric, ca. 2cm × 5mm; synandria of 3 or 4 stamens; connected filaments purple, distinct; anthers yellowish, globose, dehiscing by horseshoe-shaped slit. Appendix purple, flagellate, recurved distally following spathe limb, 9–11cm, base swollen, 4–5mm in diam., truncate and stipitate; stipe 8–10mm.