THAI FOREST BULLETIN (BOTANY) 36
Notes.— Very often cultivated in Thailand, most frequently seen as an ornamental in pots in temples and rural villages. In Lao PDR an important ‘totem’ plant in hilltribe villages. Never encountered in the wild away from human disturbance. See further notes under A. macrorrhizos.
The inflorescence description above is compiled from very poorly preserved material from Vietnam, hence it is incomplete with regard to floral details.
3.Alocasia hypnosa J.T.Yin,Y.H.Wang & Z.F.Yu,Ann. Bot. Fennici 42: 395. 2005. Fig. 2A–B.
Terrestrial or lithophytic, seasonally dormant herbs to 100 cm tall. Stem erect or tuber-like rhizome with numerous stolons and tubercles; rhizome 10 cm by 13.5 cm in diam.; stolons numerous per plant, simple, trailing horizontally or pendent, 56–110 cm long, pale green, internodes cylindric, 5.5 cm long, to 1cm diam., with light green cataphylls and tubercles produced terminally; tubercles to 4 cm by 3 cm in diam. Leaves 3–6 per plant. Petiole terete, to 104 cm by 3–7.5 cm diam., light greenish, glossy; petiolar sheath to 50 cm long, membranous; lamina triangular-sagittate, up 82 cm 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 limb; lower spathe fusiform, ca 6.5 cm by 3 cm diam., green; limb oblong-lanceolate, to 24 cm by 20 cm (flattened), fornicate, purple-pink, erect at anthesis, later flopping forwards, thence deliquescent. Spadix sessile, shorter than spathe; female flower zone cylindrical, 1.5 by 2 cm diam.; ovaries oblong, 5 mm long, style short, stigma 3–4-lobed; sterile interstice cylindrical, 5.5 by 1–1.5cm diam.; synandrodes depressed, apex nearly truncate or concave, oblong to ovate; male zone cylindrical, ca 3.5 by 2 cm, white; synandria 5–6-merous, truncate; appendix white, elongate- conic, to 16.5 cm long, 2.5 cm diam. Fruiting spathe ellipsoid, ca 3 by 2.5 cm. Fruits ellipsoid, ca 1.5 by 0.5 cm, green, ripening scarlet.
Thailand.— NORTHERN: Chiang Rai; SOUTHWESTERN: Kanchanaburi. Distribution.— Lao PDR, S.W. China (Type).
Ecology.— Humid ledges and in exposed areas of forest regrowth and deciduous, bamboo-dominated forest on karst limestone; altitude: 800–970 m.
Vernacular.— None recorded. Uses.— None recorded.
Notes.— Alocasia hypnosa is a remarkable species, both it its vegetative habit (deciduous with long runners) and in the distinctive purple-pink spathes. In habitat the long stolons enable the plants to colonize the near-vertical limestone outcrops that are their preferred habitat.
There is a possibility that Arum montana Roxb. (= Alocasia montana (Roxb.) Schott) treated by Hay as a synonym of A. macrorrhizos (Hay, 1998) is conspecific with and thus has priority over A. hypnosa. The colour plate (Roxburgh drawing no. 248) that constitutes the type of Arum montanum in many respects depicts a plant far more similar to Alocasia hypnosa than to A. macrorrhizos, especially in the inflorescence being comparatively large