Volume 11 > Part 2 > Year 2012 > Page 248 > Araceae > Homalomena

7. Homalomena truncata (Schott) Hook.f.

Fl. Brit. India 6: 535. 1893; Engl. & Krause in Engl., Pflanzenr. IV, 23Da (Heft 55): 41. 1912; Ng, Boyce & Sofiman, Gard. Bull. Singapore 62(2): 72, Fig. 3. 2011.— Chamaecladon truncatum Schott, Bonplandia (Hannover) 6(2): 369. 1858. Plate LXV.

Accepted Name : This is currently accepted.

Description : Small, solitary to weakly clumping evergreen, weakly aromatic herb to 40cm. Stem erect, older plants decumbent to creeping, 1–2 cm thick. Leaves few together; petioles 12–32 cm, green or deep purple or deep red, even in the same population; petiolar sheath 7–9 cm, margins membranous, apical portion decurrent or sometimes weakly truncate-auriculate; leaf blade ovate-triangular to cordate-hastate-triangular, 6–22 cm by 4–14 cm, base truncate to roundedtruncate to weakly hastate, apex long acuminate, with a 2–3 mm tubular mucro, coriaceous; primary lateral veins 4–9 per side, frequently drying much darker than the surrounding leaf blade; interprimary veins much finer, striate; secondary venation almost invisible. Inflorescences 1–4 together; peduncle 7–11cm, colour as for petioles; spathe oblong-lanceolate, 4–6 by ca 1.5 cm, apex apiculate, ca 2 mm long, spathe gaping at anthesis and then soon closing, deep red; spadix tapering-cylindrical, ca 5–6.5 by 0.5–0.7 cm, subequalling spathe, stipitate; stipe ca 4 mm long, reddish tinged; pistillate flower zone cylindrical, ca 1.7–2.2 cm by 4 mm; ovary depressed ovoid-globose, ca 0.5 mm diam., pale green, tinged pinkish red, with an associated clavate staminode ca equalling the height of the ovary, staminode ivory; stigma briefly slenderstipitate, capitate, smaller than the ovary diam., pinkish; staminate flower zone 4–4.5 by ca 1 cm, tapering fusiform; staminate flowers 4-androus, rhombohexagonal in plan view, ca 1 by 1.5 mm, stamens overtopped by a large connective, ivory, lowermost flowers sterile. Fruits not seen.

Thailand : SOUTH-EASTERN: Trat; PENINSULAR: Chumphon, Ranong, Phangnga, Satun, Trang, Songkhla, Narathiwat.

Distribution : S Myanmar (type), N Peninsular Malaysia.

Ecology : Disturbed primary and secondary lowland evergreen forests; sometimes on limestone. Lowlands.

Vernacular : Tao kiat (เต่าเกียด)(Trat); bon khiao (บอนเขี้ยว)(Chumphon).

Notes: Homalomena truncata is immediately identifiable by the combination of truncate to hastate leaves and the spathes ca 3–3.5 cm long. Confusion with H. griffithiiis possible although the smaller spathe (no more than 2.5 cm long) is readily diagnostic. The primary lateral veins of H. truncata dry markedly darker than the surrounding leaf blade; this is not so in H. griffithii.

There are several names applied to these larger truncate-leaved Homalomena in Peninsular Malaysia and southern Thailand, and much needs to be studied before a stable taxonomy is achieved. I have taken a pragmatic approach and adopted the earliest applicable name. The name H. occulta has been haphazardly applied to any small Thai Homalomena with unconstricted spathes and weakly hastate to truncate leaves. Homalomena occulta is based upon a now lost Loureiro type, almost certainly from Hue, in central Vietnam; the name H. occulta cannot be applied with confidence to any known species and is best abandoned, the more so since a well established name, H. truncata, exists.