A REVIEW OF ALOCASIA (ARACEAE: COLOCASIEAE) FOR THAILAND
hexagonal, flat-topped.; male flower zone subcylindric, somewhat tapered at the base, 1.2– 2.5 by 4.5–8 mm, ivory white; synandria 4–6-merous, more or less hexagonal, ca 2 mm diam.; appendix 3.5–9 cm long, about the same thickness as the male zone, demarcated from it by a faint constriction, subcylindric, distally gradually tapering to a point, very pale orange to bright yellow. Fruiting spathe ovoid, ca 4–7 cm long, glossy green. Fruits globose-ellipsoid, ca 1.5 by 0.75 cm, green, ripening orange-red.
Thailand.— EASTERN: Nakhon Ratchasima; CENTRAL: Nakhon Nayok; SOUTHEASTERN: Prachin Buri, Chanthaburi, Trat; PENINSULAR: Songkhla, Narathiwat.
Distribution.— Cambodia, Lao PDR, S Vietnam north to S.W. China, south to Peninsular Malaysia, Sumatra, Borneo, Java (Type) and Sulawesi.
Ecology.— Rainforest and regrowth understorey, in swampy areas and well drained slopes, occasionaly on rocks; altitude: 0–500 m.
Vernacular.— None recorded. Uses.— None recorded.
Notes.— This species is very widespread. In Borneo and Peninsular Malaysia it intergrades with A. lowii, which typically has broader leaf blades and is generally lithophytic on limestone.
6.Alocasia macrorrhizos (L.) G.Don in R.Sweet, Hort. Brit., ed. 3: 631. 1839; Hook.f., Fl. Brit. India 6: 526. 1893; Ridley, Fl. Malay Penins. 5: 99. 1925; Gagnepain in H.Lecomte, Fl. Indo- Chine 6: 1145. 1942; Hay, Gard. Bull. Singapore 50: 283. 1998 — Arum macrorrhizos L., Sp. Pl. 965. 1753.— Colocasia macrorrhiza (L.) Schott in Schott & Endlicher, Melet. Bot. 1: 18. 1832.— Arum indicum Lour., Fl. Cochinch. 2: 536. 1790.— Colocasia indica (Lour.) Kunth, Enum. Pl. 3: 39. 1841.— Alocasia indica (Lour.) Spach, Hist. Nat. Ve´g. 12: 47. 1846.
Massive pachycaul evergreen herb to 4 m with slightly milky latex. Stem erect to ca 1.5 m, thence decumbent. Leaves several to rather many together, clustered at the tips of stems of larger plants. Petioles to 1.3 m long, sheathing in lower –S; lamina ovato- sagittate, bluntly triangular in general outline, to 120 by 50 cm, held more or less erect, margin entire to very slightly sinuous, concolorous light green on both surfaces; primary lateral veins ca 9 on each side of the anterior costa, diverging at ca 60º; glands in axils of primary veins on abaxial side distinct; secondary venation flush with the lamina or but slightly raised abaxially, not forming interprimary collective veins or these only poorly defined; posterior lobes ca –S the length of the anterior, somewhat rotund, often overlapping, naked in the sinus in adult plants, weakly peltate in juveniles. Inflorescences paired among the leaf bases, subtended by membranous cataphylls. Peduncle barely exceeding the cataphylls at anthesis; spathe ca 13–35 cm long, constricted about 1/6th of the way from the base; lower spathe green, ovoid; limb broadly oblong-lanceolate, ca 10.5–29 cm long, cowl-like at anthesis, later reflexed, then deliquescent, membranous, pale yellow. Spadix slightly shorter than the spathe, shortly stipitate; female flower zone conic- cylindric, 1–2 by ca 1.5 cm diam.; ovaries pale green, ca 3 mm diam.; stigma sessile, 3–5- lobed, the lobes conic, yellow; sterile interstice slightly shorter than to equalling the female zone, whitish, very slightly narrowed corresponding to the spathe constriction; synandrodia rhombo-hexagonal, ca 2.5 mm diam., lower ones paler, incompletely connate