Volume 11 > Part 2 > Year 2012 > Page 123 > Araceae > Alocasia

4. Alocasia hypnosa J.T.Yin, Y.H.Wang & Z.F.Yu

Ann. Bot. Fennici 42: 395. 2005; Boyce, Thai Forest Bull., Bot. 36: 8. 2008. Plate XIV.

Accepted Name : Englerarum hypnosum (J.T.Yin, Y.H.Wang & Z.F.Xu) Nauheimer & P.C.Boyce
Pl. Syst. Evol. 300: 714. 2013.

Description : Terrestrial or lithophytic, seasonally dormant herbs to 100 cm tall. Stem an erect or tuber-like rhizome with numerous stolons and tubercles; rhizome ca 10 by 13.5 cm; stolons numerous per plant, simple, trailing horizontally or pendent, 56–110 cm long, pale green, internodes cylindrical, 5.5 by 1cm, with light green cataphylls and tubercles produced terminally; tubercles to 4 by 3 cm. Leaves 3–6 per plant; petiole terete, to 104 by 3–7.5 cm, light greenish, glossy; petiolar sheath to 50 cm long, membranous; leaf blade triangular-sagittate, to 82 by 64 cm; basal lobes naked in the sinus, membranaceous, glossy bright green; primary lateral veins pinnate, 8 pairs per side, conspicuous; interprimary veins forming a feeble collecting vein. Inflorescences 2–3 together, appearing with leaves; peduncle cylindrical, to 90 cm long, pale green; spathe to 28 cm long, constricted between lower convolute part and spathe limb; lower spathe fusiform, ca 6.5 by 3 cm, green; spathe limb oblong-lanceolate, to 24 by 20 cm (flattened), hooded, purple-pink to almost white, erect at anthesis, later flopping forwards, then deliquescent; spadix sessile, shorter than spathe; pistillate flower zone cylindrical, 1.5 by 2 cm; ovaries oblong, 5 mm long, style short, stigma 3–4-lobed; sterile interstice cylindrical, 5.5 by 1–1.5 cm; synandrodes depressed, apex nearly truncate or concave, oblong to ovate; staminate flower zone cylindrical, ca 3.5 by 2 cm, white; synandria 5–6-merous, truncate; appendix white, elongate-conical, to 16.5 by 2.5 cm. Fruiting spathe ellipsoid, ca 3 by 2.5 cm; fruits ellipsoid, ca 1.5 by 0.5 cm, green, ripening scarlet.

Thailand : NORTHERN: Chiang Mai, Chiang Rai, Nan, Lampang, Tak; SOUTH-WESTERN: Kanchanaburi.

Distribution : SW China (Yunnan – type), Laos.

Ecology : Humid ledges and in exposed areas of forests regrowth and deciduous, bamboo-dominated forests; always on karst limestone; 800–970 m alt.

Notes: Alocasia hypnosa is a remarkable species, both it its vegetative habit (deciduous with long runners) and in the distinctive purple-pink spathe limb, although populations with a much paler, or even white, spathe limb have now been located. The long stolons enable the plants to colonize widely on the often vertical karst limestone outcrops that are their preferred habitat.