Homalomena limnogena
Diminutive colonial stoloniferous helophyte up to 10 cm tall, forming diffuse patches up to 2 m or more in diameter, entire plant with a resinous odour when crushed. Roots penetrating deep into soil, main roots c.1.5 mm in diameter, laterals much finer. Stem erect to somewhat creeping and rhizome-like, c.10 mm, emitting cataphyllerous stolons to c.15 cm long, 5 mm thick, these eventually upturned, becoming rhizomatous, leafy, and emitting further stolons from the base of the rhizomatous portion. Leaves clustered, to c. 12 together; petiole up to 10 cm long and 2mm in diameter, lower half D-shaped in cross-section, upper half dorsally channelled, with the margins rounded, reddish tinged on a pale green base; petiolar sheath occupying about the lower one-quarter, wings in-rolled; leaf blade glossy medium green, lanceolate to narrowly triangular-ovate, leathery, c.8–12 cm long, 1.5–2.5 cm wide, apex acute to acuminate, shortly apiculate for about 3 mm, base cuneate to very shallowly cordate or weakly truncate, the wider leaf blades usually somewhat asymmetric basally; midrib adaxially slightly impressed, abaxially slightly prominent, with about five adaxially impressed, abaxially slightly prominent primary lateral veins on each side, primary lateral veins alternating with much fainter interprimaries and diverging at c. 45°. Inflorescence solitary; peduncle about 3 cm long, slender, c. 2-mm diameter, erect, reddish tinged with paler broken longitudinal striations. Spathe narrowly ovoid, limb about 2 cm long with a c.3mm terminal rostrum, spathe gaping at pistillate, at which stage 1 cm wide across the opening, exterior glossy yellowish green, interior greenish white with numerous minute paler punctations, uppermost part of spathe limb and rostrum reddish tinged. Spadix about 1.8 cm long, stipitate for c.4mm, stipe weakly conoid, glossy pale green; pistillate flower zone more or less cylindrical, c.6 mm long and 4mm wide; pistillate and staminate flower zones effectively contiguous, but demarcated by a ring of well-spaced globose staminodes; pistils globose with a brief (c.0.3 mm) terminal stipe, congested, c.0.5 mm diameter, very pale green. Stigma stipitate, papillate, about as wide as ovary, creamy green, producing copious stigmatic fluid at anthesis, often flooding the pistillate flower zone. Interpistillar staminodes about half the height of the pistils, one per pistil, more-or-less globose on a very short stalk, the lowermost ones pendant, glossy white. Staminate flower zone slender tapering cylindrical, widest about one-quarter of the length from the base, where about two-thirds as wide as pistillate flower zone, base narrower, c.1.8mm long by 2.5mm in diameter, slightly tapering, apex blunt, creamy white. Staminate flowers comprising (2–)4–5 stamens, those at the tip of the spadix depauperate and seemingly sterile (not releasing pollen), stamen more or less triangular in plan view, with a shallow median notch corresponding to the separation of individual thecae, c.0.5mm wide by 0.5mm long, connective weakly impressed. Fruiting spathe, fruits and seeds not observed.
Homalomena limnogena is superficially very similar to the smaller facies of Homalomena griffithii (Schott) Hook.f., but is readily distinguished by the colonial helophytic habit, enabled by the presence of mostly subterranean stolons. Homalomena limnogena is further distinguished from H. griffithii by the solitary inflorescences, the longer, c.1 cm long, red terminal rostrum and yellowish spathe exterior, and by the shorter style and larger stigma (stigma almost equalling the width of the ovary). From both other helophytic Homalomena species (H. expedita and H. rostrata), H. limnogena is distinguished by its diminutive stature and may be further distinguished from H. expedita, by the contiguous pistillate and staminate flower zones (zones not separated by a sterile warty naked interstice), and by the presence of interpistillar staminodes, and from H. rostrata by the spathe lacking a constriction between the lower part and the limb.
Only from the Type locality on Pulau Belitung, off the east coast of south Sumatera.
Homalomena limnogena forms diffuse mats in perhumid peat swamp over granite; at about 300m above sea level.