AMORPHOPHALLUS HEMICRYPTUS

PROTOLOGUE: Amorphophallus hemicryptus Hett. & J.F.Maxwell, published in Aroideana 36: 87 (2013).

Amorphophallus hemicryptus Hett.& Maxw. sp. nov. Type: CAMBODIA, Mekong River system, Kratie´ prov., Sambour distr., Gring Island, central west-side, 16 November 2006, J.F. Maxwell 06-896 (holotype, L, spirit coll.; paratypes, A, CAS, L, MO, same data and coll. number as holotype).

DISTRIBUTION: Cambodia: Cambodia.

SPECIES DESCRIPTION:

Small, seasonally dormant, deciduous, perennial herb, tuberous. Tuber vertically elongate, 1 cm in diam., ca. 4 cm long, pale brown outside, whitish and pale yellow inside. Leaf unknown but seasonally deciduous.

INFLORESCENCE:

Inflorescence developing separate from leafy phase, solitary or two to three developing in sequence, all held at ground level; peduncle ca. 1 cm long, 2–3 mm in diam., subterranean; spathe ovate, 2–3.5 cm long, 1.5–3 cm across, base loosely convolute, inside smooth, dark purple, base and limb not separated by a constriction, limb oblique, acute, margin slightly rolled inwards, dirty whitish outside with minute darker speckles, inside limb as outside, scape, including bracts in soil, dull whitish. Spadix sessile, ca. 6–12 cm long; female zone 3 mm in diam., consisting of ca. 4–8 pistils in one row, crowded on a narrow zone on the lowermost part of the spadix, their long axes subparallel to the spadix axis; sterile, naked zone between female and male part 3 mm long, 1 mm in diam.; male zone cylindric, 0.7–1.5 cm long, 0.3–0.4 cm in diam., flowers distant; appendix myosuroid, 5–10 cm long, 2–3 mm in diam., acute, smooth, whitish with numerous pale pinkish-greyish speckles. Pistil broadly lageniform; ovary 1 mm long, 2–2.5 mm in diam., 2–3-locular, strongly constricted between the locules; style slightly conical, 0.7 mm long, 0.8 mm in diam. at the base; stigma very thin, ca. 8 mm across, shallowly bilabiate, surface verruculate. Male flowers 1–3-androus; filaments absent or 0.5 mm long, fused; anther globose, 0.9–1 mm in diam., creamy with purplish speckles, pores apical.

ECOLOGY:

Found in shaded, fire-damaged, very degraded, deciduous, seasonal hardwood forest lacking bamboo; around presently dry stream channels; shale bedrock

ETYMOLOGY:

From Greek hēmi-, “half” or “partly,” and kryptos, “hidden” or “concealed,” meaning “partly hidden.” Although the original description does not explicitly explain the name, it likely refers to the species’ remarkably cryptic flowering habit: the peduncle and bracts remain underground, leaving the diminutive inflorescence sitting directly at the soil surface

NOTES:

1. Amorphophallus hemicryptus differs from Amorphophallus polyanthus Hett. & M. Sizemore (eastern Thailand) by the presence of a sterile zone on the spadix, and the male flowers not congested. Amorphophallus hemicryptus is distinguished from Amorphophallus terrestris Hett. & C. Claudel (eastern Thailand) by the same characters, and additionally, by the much longer and thinner spadix appendix.

2. The discovery of Amorphophallus hemicryptus (then unnamed) by Dr. J.F. Maxwell was announced earlier (Bezuijen, 2007, Maxwell, 2009). The reports are part of a World Wildlife Fund project investigating biodiversity along the Mekong River.

3. Although no molecular data are available for Amorphophallus hemicryptus, its morphology indicates it is part of a small clade of minute to small species hitherto known only from eastern Thailand (Amorphophallus polyanthus, Amorphophallus sumawongii (Bogner) Bogner and Amorphophallus terrestris). The new species strongly resembles both Amorphophallus polyanthus and Amorphophallus terrestris (Hetterscheid & Claudel, 2012a) but differs clearly from both by possessing a sterile, naked zone on the spadix, between female and male zone.

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus hemicryptus Hett. & J.F.Maxwell

2. Aroideana 36: 87 (2013) — protologue.