Arisaema lackneri Engl.

Epiphytes, dioecious. Tuber depressed globose, ca. 5 × 10cm, renewed seasonally, purple outside with brown spots 1–1.5mm in diam.; roots whitish, 2–7 cm × 1–2mm. Leaf solitary, coetaneous with fruit; petiole green, without spots, cylindric, 20–30 × ca. 1cm, smooth; leaf blade greenish, membranous, 3-foliolate; leaflets petiolulate; central leaflet with petiolule ca. 15mm, blade ovate, ca. 20 × 10cm, base cuneate, apex acute; lateral veins numerous; collective vein 2–3mm from margin; lateral leaflets with petiolule 8–11mm, blade obliquely ovate-lanceolate, ca. 21 × 8cm, base obliquely cuneate, apex acuminate with filiform tail 5–8mm. Inflorescences unisexual, appearing before leaf; peduncle white, terete, ca. 26 × 0.3cm (male), ca. 25 × 1cm (female), surrounded by cataphylls; cataphylls 3, pale green, oblong, 18–23cm, membranous, apex obtuse. Spathe tube green, cylindric, ca. 6 × 1.5cm, throat margin broadly auriculate, strongly outwardly recurved; limb arched, greenish purple, ovate-lanceolate, ca. 6 × 5cm, apex acuminate with a purple tail to 60cm. Female spadix densely flowered; ovaries green, 1-loculed, ovoid; stigmas sub-sessile, disciform; ovules 5 or 6, basal, erect; appendix as in male spadix. Male spadix with basal fertile part cylindric, ca. 3.8 × 0.5–0.6cm, densely flowered; synandria subsessile, purple; anthers 4–6, subglobose, dehiscing by an apical slit; appendix sessile, greenish, cylindric, ca. 3.8 × 0.3cm, apex obtuse, with a few subulate neuter flowers in basal part. Infructescence cylindric, ca. 5.2 × 1–1.5cm.