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Amorphophallus 'John Tan'





Nomenclatural Notes:


Published in:

Aroideana Journal of the International Aroid Society, Inc.

Volume 35, Number 1 (2012); Pages 103-108

Released Year:




Cultivar Type:



Ralph D. Mangelsdorff


Cyrille Claudel

Seed Parent:

Amorphophallus variabilis

Pollen Parent:

Amorphophallus titanum

Base Species or Cultivar:


Cultivar Origin:

On the 23rd of May 2002, Mangelsdorff applied pollen of Amorphophallus titanum on the stigmas of one inflorescence of Amorphophallus variabilis. The berries took some five months to mature and yielded five viable seeds among many sterile degenerate ones. Some of the plantlets perished very soon but two survived. Because of heavy infestation with nematodes, the plants were transferred in a rescue mission to the hands of Wilbert Hetterscheid. They were cultivated for a few years in the Amorphophallus research collection in the Wageningen University Botanical Gardens in the Netherlandsand finally cleared of nematodes. Due to the sudden closure of the botanical gardens in Wageningen, a new shelter was required. One plant was handed over to the Botanical Garden of Leiden University, The Netherlands, and the second one to the Botanical Garden of Hamburg University, Germany, in 2008, where it was nursed by the first author, and was finally brought to flower in June 2011. This is the plant we describe here. The Leiden plant is still alive but hasn’t flowered yet.

Name Origin:

Out of gratitude, Claudel chose to name this particular cultivar in honor of a friend and his encouraging help.

Growth Habit:

Tuber depressed globose, to at least 24 cm in diam. and to 15 cm in height, weighing ca. 6 kg, surface whitish-brownish with many raised areas, no offset development.

Leaf Blade:

Leaf solitary; cataphylls to 50 cm long,brownish, with white lichenlike spots; petiole to 1.45 m. long, to 8 cm in diam. (base), turgid, smooth, dark green or brownish, with large, whitish lichen-like spots similar to the ones on the petiole of A.titanum; lamina to 1.20 m in diam., poorly dissected in young plants, resembling a young A. titanum lamina, highly dissected in mature plants, showing more resemblance with a typical A. variabilis leaf; leaflets elliptic-lanceolate, to 20 cm long, to 7 cm in diam., acuminate, leathery, upper surface slightly glossy.

Bloom and Fruit:

Inflorescence solitary; peduncle to 55 cm long, ca. 6 cm in diam., coloured as petiole but darker altogether; spathe campanulate, triangular, to 45 cm long, limb spreading, rim-shaped, margin slightly plicate similar to A. titanum but not as strong as in the latter, veins of the limb strongly raised, outside base dirty greenish yellow with whitish spots, base
inside verrucate and slightly purple at the base, with abroad yellowish band above and rich purple-red in the upper part. Spadix sessile, longer than spathe, ca.1 m long; female zone 6 cm long, flowers congested; male zone slightly obconic, 8 cm long, flowers congested like in A. variabilis; appendix elongate fusiform, obtuse, ca. 80 cm long, ca. 9 cm in diam.,base truncate and expanded overarching the male zone, similar as in A. titanum, dirty yellowish white, slightly rugose. Ovaries ovate, ca. 5 mm in diam., 3 mm high, orbicular, base yellowish, turning purple in the upper part; style 5 mm long, blackish purple; stigma elliptic, 1–2 mm in diam., ca. 1 mm high, orange, strongly bilobate. male flowers producing abundant pollen. Pollen fertility unknown. Propagation by vegetative means.

Distinguishing Characteristics:

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