Arisaema arunachalense

Arisaema arunachalense A.Nangkar, A.P.Das & H.Tag, (as A. arunachalensis ), Pleione View in CoL 11(2): 482. 2017. Type: INDIA , Arunachal Pradesh, East Siang District, Pasighat, 560 m, 08.05.2015, A. Nangkar & Hui Tag 026 (ASSAM). Fig. 2 View Figure 2

Dioecious, perennial herbs, c. 70 cm tall. Subterranean stem a corm, 1–2.2 cm long, 2.5–4.3 cm diam., depressed globose. Roots many, from the top of the corm; stolons absent. Cataphylls 2, to 18 cm long, one short and other long. Leaves 1, held above the inflorescence; petiole 10–70 cm long, terete, white, generally pinkish towards the base, mottled with purple patches and spots; leaflets 5–9, radiate, 14–34 cm long, 3–9.5 cm wide, broadly obovate-lanceolate, long-acuminate (c. 2 cm long) at apex, base gradually attenuate; slightly unequal in size, pale green above, whitish below, marginal veins extending from base to tip. Sheathing pseudostem c. 18 cm long, mottled as in petiole. Inflorescence arises just above the cataphylls, 12–18 cm above from the corm; peduncle much shorter than petiole, 25–34 cm long, exserted by 7–10 cm long from the pseudostem, mottled as in petiole, nodding at fruiting. Spathe dull-white on both surfaces; tube of spathe cylindric, funnel-shaped towards mouth, 20.3–23.2 cm long, dull-white with purple longitudinal lines on both surfaces, slightly constricted at the mouth, margins of the mouth dilated to a revolute auricular extension; limb wider than the tube, sagittate-ovate, caudate-acuminate at apex, forming a slender tail (c. 5 cm), dull white, densely purple-blotched, sometimes blotches coalescing. Female spadix sessile, 9.5– 11.2 cm long, cylindric with a narrow fertile region, mottled with purple blotches, sterile zone with 14–17, dark purple subulate neuters; appendix stipitate, cylindric with swollen apex (looks like the tip of drum-stick), dark purple and white mottled, exceeding the mouth of the tube; pistils many, sessile, compactly arranged, ovoid, green, stigma short, continuous, whitish. Male spadix smaller than female, with many pistillodes towards the base, neuters absent, sterile male flowers at the middle and fertile male flowers above; male flowers sessile, scattered at the middle, crowded distally, consisting of 4 or 5 dark purple anthers. Fruiting spike not seen.

Flowering & fruiting: April–October.

Habitat: On the floor of dense evergreen forests with thick humus at an elevation of 500–700 m.

Distribution: India (North-East Himalayas) , endemic.

Notes: Arisaema arunachalense is close to A. echinatum (Wall.) Schott in having an echinate spadix appendix but can be distinguished by its longer pseudostem, densely purple blotched spathe limb and swollen tip of appendix as opposed to very short pseudostem, white striped green or purple spathe limb and obtuse apex of spadix appendix in the latter. This species thrives in tropical or subtropical evergreen forests at elevations 500–700 m whereas A. ciliatum grows above 2500 m. Authors used the epithet ‘ arunachalensis ’ in the protologue. The genus name being in neuter gender, the epithet should be corrected to ‘ arunachalense’. The description provided here is taken from the protologue.