AMORPHOPHALLUS KIENLUONGENSIS
PROTOLOGUE:Amorphophallus kienluongensis V.D.Nguyen, Luu & Hett., published in Blumea 61: 1 (2016).
Amorphophallus kienluongensis V.D. Nguyen, Luu & Hett., sp. nov. Diagnosis: Amorphophallus kienluongensis resembles Amorphophallus brevispathus in having a spathe shorter than the spadix and the male flowers clustered in groups of 6 or more. It differs from Amorphophallus brevispathus in the stigma diameter exceeding that of the ovary and in having a tuber without long rhizomatous offsets. Type: Nguyen Quoc Dat & Luu Hong Truong, KG008 (holotype SGN), KG 001 (paratype VNMN, leaf), KG002 (paratype VNMN, inflorescence), KG003 (paratype L, leaf), KG004 (paratype L, inflorescence), KG 010 (paratype HN), Viet Nam, Kien Giang Province, Kien Luong District, Ba Tai Hill, 2 June 2011; KG008 (paratype HN, leaf collected from the type-plant in cultivation, 2012).
DISTRIBUTION: Vietnam: Vietnam.
DISTRIBUTION NOTE: Vietnam: Kien Giang Province, Kien Luong District — the Kien Luong karst system (Khoe La, Hang Tien, Chua Hang and Ba Tai hills)².
SPECIES DESCRIPTION:
Seasonally dormant, tuberous herb, 20–50 cm tall. Tuber globose or slightly elongate, producing depressed globose offsets, 3.5–7 cm long, 2–6 cm thick; flesh white. Leaf solitary. Petiole cylindric, 24–90 cm long, 1–2.6 cm diam at base, smooth, light green or dull brownish green. Lamina moderately decompound, 20–55 cm diam. Leaflets elliptical, elongate obovate, or lanceolate, 6–18 cm long, 3–5 cm across at the widest point, base attenuated, oblique, acute, or acuminate, acumen 1.5–2 mm long, upper surface medium to dark green, glossy; lateral veins abundant, prominent on the lower surface, distance 6–7 mm between veins, sometimes with intermediate veins; collective vein 2–4 mm distant from margin.²
INFLORESCENCE:
Inflorescence appearing without the leaves. Peduncle 15–45 cm, 0.7–2 cm diam at base, smooth, light green. Spathe considerably shorter than spadix, broadly triangular, 3.5–7 cm long, 5–9 cm wide at the base, enclosing the entire fertile part of the spadix, base strongly convolute, whitish green on both surfaces, slightly darker green at the base, inside surface with a prominent wax layer. Spadix much exceeding spathe, sessile, 10–15 cm long; female portion slightly obconic, 1.3–1.5 cm long, 1–1.2 cm diam at the base, 1.3–1.5 cm diam at the apex, ovaries distant; male portion obconic, 4.0–5.4 cm long, 1.5 cm diam at the base, 2.4 cm diam at the apex; appendix elongate-conic, 6–11 cm long, 2–3 cm diam at the base, top acute or obtuse, surface smooth, off-white. Ovary globose, pale green, unilocular, 1 mm high, 2 mm diam, ovule solitary, basifix; style prominent, thick, whitish green, 1 mm long; stigma 1.2–2.2 mm diam, wider than ovary, dirty whitish, disciform with a concave depression, slightly lobed, surface uneven. Male flowers consisting of 3–5 stamens but flowers from the base to the top of the male zone increasingly clustered to form groups with 8 or more stamens; stamens 0.8–1.5 mm long, 1.5–3 mm diam; filaments very short, 0.2–0.4 mm long; anthers truncate, 1 mm long, yellow, connective very thin, rupturing fully at male anthesis to create a single common pore. Infructescence slightly elongate, obconical, to 7 cm long and 2 cm diam at the base and 3 cm at the apex, berries lax, 1.6–2.0 by 1.0–1.4 cm, elongate ovate, shiny dark blue when mature.²
ECOLOGY:
Found in coastal forests on karst limestone; flowering in June and fruiting in September; altitude: 5–50 m²
ETYMOLOGY:
The species epithet kienluongensis is derived from the name of the Kien Luong district of the Kien Giang province, Vietnam.²
NOTES:
1. The combination of characters in Amorphophallus kienluongensis of male flowers in large groups, a rupturing connective, and berries ripening blue suggests the species to be a member of a subclade of five other species with this same unique character combination: Amorphophallus atrorubens (Thailand), Amorphophallus brevispathus (Thailand), Amorphophallus gallowayi (Thailand), Amorphophallus interruptus (northern Vietnam), and Amorphophallus prolificus (Thailand). As yet unpublished molecular phylogenetic information based on 130 species resolved these species as a monophyletic group with full statistical support.²
2. Amorphophallus kienluongensis is known to occur only on several small adjacent isolated limestone hills including Khoe La, Hang Tien, Chua Hang, and Ba Tai in the Kien Luong district. Khoe La is quarried for cement manufacture, and it is foreseen it will be destroyed within the next years. The area in which the species grows is less than 3 km2 and combined with threats from quarrying the species is recommended to be ranked as globally Critically Endangered (CR) according to the IUCN Red List criteria.²
STORY:
STORY TITLE: The hill that becomes cement
Amorphophallus kienluongensis has one of the smallest addresses of any aroid: a handful of small, isolated limestone hills — Khoe La, Hang Tien, Chua Hang, Ba Tai — rising out of the Mekong Delta flatlands in the Kien Luong district of Kien Giang Province, southern Vietnam. The entire area in which the species grows is less than three square kilometres. It was only discovered in 2011, flowering leafless on Ba Tai Hill in June, and described in Blumea in 2016.
Those same hills are the delta's only source of limestone, and limestone is cement. Khoe La is already being quarried for cement manufacture, and the describing authors foresee its destruction within years — which is why, in the very paper that gave the species its name, they recommended it be ranked globally Critically Endangered. It is a rare thing for a plant to be born into science with its obituary already drafted: the hill it grows on is being carried away by the truckload.
The species is a tuberous geophyte of the karst faces, dormant for part of the year and flowering before its single leaf appears — a lifestyle built for surviving on thin, seasonal limestone soils. It survived unnoticed within sight of the delta's rice fields until 2011. Whether it survives the cement industry is the question the species now waits on.
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus kienluongensis V.D.Nguyen, Luu & Hett.
2. Blumea 61: 1 (2016) — protologue.
3. Alan Galloway — Amorphophallus kienluongensis, alangallowaybotanicals.com.