AMORPHOPHALLUS TITANUM
PROTOLOGUE: Amorphophallus titanum (Becc.) Becc., published in Bullettino della R. Società Toscana di Orticultura 4(2): 46-51 (1879).
Amorphophallus titanum (Becc.) Becc. ex Arcang., Bull. Soc. Tosc. Ortic. 4(2): 46-51 (1879). Conophallus Titanum Becc. in Bull. della R. Soc. Tosc. di Orticultura, anno III, p. 271 e 291. Amorphophallus Titanum Becc. in Herbario R. Musei Florentini. Rhizoma crassum, tuberiforme, subsphericum, basi plerumque annulatim constricto, saepe diam. cent. 50 attingens. Folium post anthesin protrusum, maximum, altitudine 2-5 metrale, petiolo crasso, cylindrico, laevi, nitido, pallide viridi, maculis subrotundis albidis crebre consperso, 2-3 m et ultra longo, 10 cent. c. crasso, cruribus, seu segmentis primariis tribus dichotomo-pinnatosectis, segmentis extremis seu foliolis, ovatis vel oblongis, membranaceis, fere ad basin usque discretis, abrupte et longiuscule acuminatis. Scapus petiolo valde similis, a 50 cent. ad 1 m et ultra longus, 8-10 cent. crassus, inferne leviter conicus. Spatha lata, basi convoluta, campanulata: a tertia parte inferiore ad marginem longitudinaliter et dense crispata, ambitu grosse dentata, dentibus triangularibus subobtusis, extus viridi-pallida, intus purpurascens, verrucis omnino destituta, dimidio spadice paullo brevior. Spadix 1 m 60 longus. Plantam hanc in Sumatra occidentali, prope Ajer Mantcior et Kaju Tanam ubi ab incolis Krubut appellatur, sylvis opacissimis solo trachytico superimpositis vegetantem detexit cl. O. Beccari.
SYNONYMS:
HOMOTYPIC SYNONYMS: Conophallus titanum Becc. in Bull. Soc. Tosc. Ortic. 3: 271 (1878)
HETEROTYPIC SYNONYMS: Amorphophallus selebicus Nakai in Bull. Tokyo Sci. Mus. 22: 1 (1948)
DISTRIBUTION: W. Sumatera: Sumatra.
DISTRIBUTION NOTE: Sumatra: the west of the island, near Ajer Mantjor and Kaju Tanam, where Beccari found it. It was later gathered by Forbes in the Barisan range on sandy ground, and by the Kling river.⁶.
SPECIES DESCRIPTION:
Translated from protologue: Rhizome thick and tuber-like, underground, subspherical, varying with the age of the plant and often more than 50 cm across, usually with a hollow on top in which the bud sits and a circular constriction at the base that makes it somewhat resemble the corm of a crocus. The leaf always develops after flowering. It is very large, from 2 to 5 m high and more than 6 m across when spread. The petiole rises vertically and in the largest individuals reaches 3.5 m; it is cylindrical, smooth, light green and densely scattered with almost circular whitish spots, so that it resembles the bark of a lichen-covered tree. Above, it divides into three branches, as thick as a leg at the base and more than 3 m long. These fork several times and spread into a pinnatisect blade whose segments are membranous, ovate or oblong, abruptly acuminate at the tip and running down the veins at the base, reaching - especially towards the margin - as much as 4 dm long and 10-14 cm wide, with smaller segments alternating among the larger. The secondary veins are prominent beneath, spreading and nearly parallel, and run into a vein set about 4 mm from the margin.²
INFLORESCENCE:
Translated from protologue: The scape is vertical, smooth and polished, spotted as the petiole, 50 cm long and 10 cm across, slightly conical at the base where its circumference is 0.9 m. The spathe is very large and bell-shaped, up to 70 cm deep, widening gradually from the base with a very open mouth, densely crisped from the lower third to the margin, which is coarsely toothed with short, nearly blunt triangular teeth. It is purplish and entirely without warts within, pale greenish outside, and can reach 0.8 m across; the convolute part carries a few barely visible whitish spots outside, the ground there is greenish and the limb is deep blackish purple. The spadix is about 1.5 m long in the largest individuals. The reproductive organs occupy about 20 cm at its base: the female flowers fill the lower two-thirds of that, in a nearly cylindrical zone, and the male flowers the upper third, which is shaped like a spinning top with a strongly projecting upper edge. The female flowers are numerous and set in parallel spiral series almost touching, each with a globose-conical purplish ovary carrying a cylindrical style about twice the length of the ovary and a nearly hemispherical, obscurely 2-3-lobed, dull yellow stigma; the ovary is three-chambered, sometimes two, each chamber with a single anatropous ovule attached at its base on the inner angle. The male flowers are simple stamens with a very short thick filament and a nearly globose, obscurely two-lobed, very blunt, four-chambered anther whose chambers lie close in two pairs and which opens at the apex by two pores; the stamens touch one another and form a layer covering the whole fertile surface. Above the sexual organs the spadix is drawn out into an elongate conical appendix, not wrinkled and regular in outline, ending bluntly, dirty yellow below and livid above. The fruiting spadix reaches 60 cm on a peduncle 1.5 m long and 10 cm across. The fruits are numerous, ellipsoid, the size and shape of a common plum and bright scarlet, so that the whole infructescence resembles a large cylinder covered in small tomatoes; the pericarp is thick and fleshy and each fruit holds 2-3 large oblong seeds, greenish outside, convex on the outer face and flat or keeled on the inner.²
ECOLOGY:
Found in very deeply shaded forest, on ground rich in leaf litter over the breakdown of trachyte rock. When the inflorescence opens, the appendix gives off a stench like putrefying meat and reaches a temperature well above that of the surrounding air.²
ETYMOLOGY:
Derived from the Titans, the primordial giants of Greek mythology, referring to the extraordinary dimensions of the species. Amorphophallus titanum produces the largest unbranched inflorescence in the Araceae and may develop a spadix several meters tall, making the mythological comparison particularly apt.
NOTES:
1. Beccari found the plant in fruit near Ajer Mantjor on 6 August 1878 and in flower near Kaju Tanam on 5 September, a short distance away.²
2. ⚠ The diagnosis and the description were drawn up from several specimens in leaf, two in fruit, and one flowering specimen - the only one found. Everything the original account says about the flower rests on that single plant.²
3. The name has a compound authority for a reason. Beccari published the plant as Conophallus titanum in the same Tuscan horticultural bulletin the year before, and wrote Amorphophallus titanum on his herbarium sheets in Florence, but a name on a herbarium label is not a published name. Arcangeli printed the Latin diagnosis that validates the combination, assembled from material and notes Beccari supplied together with some observations of his own.²
4. Much of the original paper is given over to arguing that the plant is distinct from Conophallus giganteus. It differs, the author says, in leaf spots 1-2 cm wide rather than large ones, a longer, widely spreading, bell-shaped and densely crisped spathe that is entirely without warts inside and neither gaping nor wavy-edged, and globose-conical rather than angular ovaries carrying a long style.²
5. Beccari preserved flowers, fruits and leaves in spirit and dried others, and sent to Europe a quantity of seed addressed to the Marchese Bardo Corsi-Salviati along with six cases of tubers. A good part of the consignment arrived, and the museum in Florence came to hold a whole dried spathe and spadix.²
6. A plant in cultivation at Kew flowered there in June 1889, and one at Calcutta in March 1882.⁶
7. Its local name in western Sumatra is recorded as krubut.²
8. Where the translated protologue has the anthers opening at the apex by two pores, a later anatomical study of the inflorescence describes them as opening by terminal slits to disperse the pollen.⁷
9. In July 1995, David Leedy donated his aroid collection of more than twenty-five years to the Huntington Botanical Gardens; it included seventeen Amorphophallus titanum plants, five of which, according to his notes, were then in their third growing season in 5-gallon containers.⁸
10. Ron McHatton imported about 4,000 Amorphophallus titanum seed from Troy Davis, about three years before April 2008, while working for Worldwide Orchids. He reported that the seed had been collected for Davis in Indonesia from a moderately high-elevation population that is not cold growing but briefly sees mid-60s°F.⁹,¹⁰ Davis had located populations at both low and high elevations; to McHatton's knowledge, all of the imported seed came from the higher elevation, and the seedlings later sold by EFG Orchids of DeLand, Florida came from two collections.¹⁰
11. At Plant Delights Nursery in Raleigh, North Carolina (USDA zone 7b), Tony Avent reported that plants from Symon's original seed collection of Amorphophallus titanum were left outdoors in autumn until temperatures fell to about 35°F (2°C) and then brought indoors, after which all of them went dormant within a couple of weeks. After nearly ten years of this routine he reported perfect success, with the plants usually re-emerging between June and July.¹¹
12. In October 2007, Bill Weaver reported that his Amorphophallus titanum, grown in a greenhouse kept at a minimum of 65°F, had been going dormant on a regular schedule for most of its 12 years.¹²
13. Ron McHatton, who at one time was growing about 4,000 Amorphophallus titanum from seed, found soil temperature important, at least in juvenile plants, for keeping them growing. The optimum appeared to be near 80°F, and plants tended to overheat if it went much higher. He noted that wet potting mix can be as cool as 50°F through evaporation when the air is 60°F.¹³
14. At the University of Missouri-St. Louis, Kathy Upton grew twelve Amorphophallus titanum seedlings from seed that Jim Symon supplied, planted in February 1995.¹⁴,¹⁵ One of the twelve opened on the night of May 2nd, 1998, about three years and three months after planting, with a miniature inflorescence about two feet tall, on a tuber she judged close in size to that of a dormant sibling that weighed 24 ounces and measured 5 inches across.¹⁵,¹⁶,¹⁷ Wilbert Hetterscheid, who had picked the seed with Symon from a giant infructescence, vouched that the seed Symon sent to growers was genuine Amorphophallus titanum.¹⁸ A second plant from the same batch was reported in flower on June 20th, 2001, six years and four months after planting; its tuber, when repotted in dormancy, measured 12 inches across and weighed 10 pounds.¹⁹,²⁰ These are first-hand grower reports rather than a measured trial, and the earliest flowering was of a miniature inflorescence, but they put the low end of the seed-to-flower interval for Amorphophallus titanum in cultivation nearer three years than six.
15. On October 9th, 2004, Alistair Hay of the Royal Botanic Gardens Sydney wrote that the garden's horticultural staff had deliberately overfed a subset of its Amorphophallus titanum plants; the pots toppled as the tubers swelled, and one plant, at 15.5 kg, produced a flower.²¹
16. In December 2010, an Amorphophallus titanum flowered at Inhotim Botanical Garden in Brumadinho, Brazil, about ten years after sowing, reported as the first flowering of the species in Latin America. Eduardo G. Gonçalves, a researcher and curator at the garden, had raised the plant from seed received from Selby Gardens in 1999 or 2000; only one of the three or four seeds survived, and the tuber weighed about 13 kg in dormancy.²²,²³
17. The spathe of cultivated Amorphophallus titanum overlaps in either direction as it unwraps. One grower reported that every plant that had flowered for them wrapped left-handed (the term was not defined), while every plant at the University of Wisconsin wrapped right-handed.²⁴ Two other growers posted blooms with the spathe wrapped left over right, one recalling that arrangement as seeming the less common.²⁵,²⁶
18. Leaf-blade cuttings of Amorphophallus titanum have rooted in cultivation. Anne Olivier reported a single cutting, taken from a yellowing leaf: a 3 cm leaf branch with its blade trimmed to about 3 cm wide, its base set in rooting powder and then in potting mix with coarse sand added, on ground heating at 27°C (81°F). After three months the cutting had a stem thickening of about 5 mm and two roots, though no leaf had yet formed.²⁷,²⁸ Kathy Upton photographed five rooted cuttings, made in December 1997 from the leaf blades of several Amorphophallus titanum plants grown from seed.²⁹
19. Two growers reported propagating Amorphophallus titanum from leaf cuttings on the Aroid-L mailing list in September 2003. Bill Weaver set two leaflets, one treated with Rootone F and one with Olivia's Cloning Gel, each in a six-inch pot of fine vermiculite, sand and perlite zipped into a plastic bag under fluorescent light. The leaflets stayed green for almost a year; after they had rotted away, the Rootone F leaflet had made three bulblets, about 3 to 9 mm across, and the Cloning Gel leaflet two cylindrical midrib growths (about 2.5 cm by 7 mm and over 6 cm by 2 cm), the larger bearing two bulblets of 5 and 15 mm. He planted them all in April 2003, and the first new shoots had come up in the Cloning Gel pot by the time he wrote.³⁰ Doug Ewing, greenhouse manager at the University of Washington, used no hormone: a 12-inch piece of leaf with its midvein, stuck in a cube of rockwool and sealed in a bottle terrarium at nearly total humidity, formed a tuber in several months, after which the original leaf tissue typically died and a new leaf emerged.³¹
20. Wilbert Hetterscheid stated that Amorphophallus titanum does not produce offsets, which he defined as true side tubers or rhizomes that develop on the mother tuber and separate from it by themselves in their first year or at the start of their second. Tubers of this species that divide do so when adventitious buds develop into new tubers (splitting), as reported at second hand for a tuber kept in too small a pot and for one whose central bud was destroyed.³²,³³,³⁴
21. Amorphophallus titanum is generally described as not producing offsets, but Doug Ewing, greenhouse manager at the University of Washington, reported on the Aroid-L mailing list that he had grown plants that offset: they did not multiply like potatoes, but occasionally yielded an extra tuber or two.³⁵
STORY:
STORY TITLE: The only one they found
The first titan arums grown in Europe came from the consignment of seed and tubers Odoardo Beccari shipped home after he saw the species flowering in Sumatra on September 5th, 1878. Many of the plants that have flowered in collections in the United States since come from a different source: wild seed that Dr. James (Jim) Symon collected and distributed.³⁶,³⁷ Julius Boos credited Symon with bringing the giant Amorphophallus species into cultivation by seed, and Seán A. O'Hara received some of the titan arum seed that Symon distributed.³⁸,³⁹
Beccari had come upon the species a month earlier, on August 6th, near Ajer Mantjor on the west coast, and it was in fruit — a column of scarlet berries that his describer would later compare to a cylinder covered in small tomatoes. The flower he found at Kaju Tanam, a short distance away, in forest so shaded the account calls it opacissima, growing on ground thick with vegetable litter over weathered trachyte. The local name was krubut.
What is easy to miss is how thin the material was. When the description of the largest inflorescence in the family was finally printed, its author noted plainly that the diagnosis and description rested on several specimens in leaf, two in fruit, and a single flowering plant — l'unico trovato, the only one found. Everything the nineteenth century knew about how this plant flowers came from that one individual.
Beccari did two things immediately. He preserved what he could, in spirit and dried, so that Florence ended up with a whole spathe and spadix. And he shipped the species to Europe alive: a quantity of seed addressed to the Marchese Bardo Corsi-Salviati, and six cases of tubers. A good part of the consignment arrived. Eleven years later a plant raised from that seed opened at Kew.
The naming was almost as roundabout. Beccari published the plant as Conophallus titanum in a Tuscan horticultural bulletin, and wrote Amorphophallus titanum on his herbarium sheets in Florence — but a name on a label is not a published name. It fell to Giovanni Arcangeli, in the same bulletin in 1879, to print the Latin diagnosis that made the combination real, assembled from the material and notes Beccari handed him. Arcangeli spent much of the page arguing that the plant was genuinely distinct from Conophallus giganteus, whose author had said his own species differed from its nearest relative chiefly in being larger and smoother-stalked. So the standard authority for the most famous plant in the family is a compound one, and the man who wrote the description had never seen it alive.
He recorded something else on that page which took the rest of botany decades to take seriously. When the inflorescence opens, he wrote, the appendix gives off a stench like putrefying meat and shows a temperature well above that of the surrounding air.
HYBRIDS:
Amorphophallus ‘DiGeSt’ (Amorphophallus variabilis ‘Sluka’s Dark Giant’ × Amorphophallus titanum)
Amorphophallus gigas × Amorphophallus titanum
Amorphophallus gigas × (Amorphophallus titanum × Amorphophallus ‘John Tan’)
Amorphophallus ‘John Tan’ (Amorphophallus variabilis × Amorphophallus titanum)
Amorphophallus lambii × (Amorphophallus variabilis × Amorphophallus titanum)
Amorphophallus titanum × Amorphophallus ‘John Tan’
(Amorphophallus titanum × Amorphophallus ‘John Tan’) × Amorphophallus lambii
Amorphophallus titanum × Amorphophallus konjac
Amorphophallus variabilis × Amorphophallus titanum
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus titanum (Becc.) Becc.
2. Bullettino della R. Società Toscana di Orticultura 4(2): 46-51 (1879) — protologue.
3. Alan Galloway — Amorphophallus titanum, alangallowaybotanicals.com.
5. iNaturalist: Amorphophallus titanum
6. Das Pflanzenreich IV.23C (Heft 48): 86–87 (1911)
8. Aroid-L mailing list, David Leedy, August 1st, 1999
9. Aroid-L mailing list, Ron McHatton, April 8th, 2008
10. Aroid-L mailing list, Ron McHatton, April 8th, 2008
11. Aroid-L mailing list, Tony Avent, September 4th, 2001
12. Aroid-L mailing list, Bill Weaver, October 22nd, 2007
13. Aroid-L mailing list, Ron McHatton, November 27th, 2007
14. Aroid-L mailing list, Kathy Upton, April 20th, 1998
15. Aroid-L mailing list, Kathy Upton, April 27th, 1998
16. Aroid-L mailing list, Kathy Upton, April 29th, 1998
17. Aroid-L mailing list, Kathy Upton, May 4th, 1998
18. Aroid-L mailing list, Wilbert Hetterscheid, May 1st, 1998
19. Aroid-L mailing list, Kathy Upton, June 13th, 2001
20. Aroid-L mailing list, Kathy Upton, June 20th, 2001
21. Aroid-L mailing list, Alistair Hay, October 9th, 2004
22. Gonçalves, E.G., Viana, P.L., Monteiro, J.A.V., Leal, W.B., Dias, A.N. & Custódio, R.M. 2011. Flowering Amorphophallus titanum (Araceae) at Inhotim Botanical Garden – The First Blooming Event of this Species in Latin America. Aroideana 34: 123–128
23. Aroid-L mailing list, Eduardo G. Gonçalves, December 17th, 2010
24. Aroid-L mailing list, Kathy, October 25th, 2011
25. Aroid-L mailing list, Susan B, December 19th, 2012
26. Aroid-L mailing list, a member, December 20th, 2012
27. Aroid-L mailing list, Anne Olivier, February 3rd, 1998
28. Aroid-L mailing list, Anne Olivier, February 4th, 1998
29. Aroid-L mailing list, Kathy Upton, April 23rd, 1998
30. Aroid-L mailing list, Bill Weaver, September 15th, 2003
31. Aroid-L mailing list, Doug Ewing, September 18th, 2003
32. Aroid-L mailing list, Wilbert Hetterscheid, May 22nd, 2006
33. Aroid-L mailing list, Julius Boos, May 21st, 2006
34. Aroid-L mailing list, Bernhard, May 23rd, 2006
35. Aroid-L mailing list, Doug Ewing, September 10th, 2002
36. Aroid-L mailing list, Julius Boos, July 23rd, 2004
37. Aroid-L mailing list, Julius Boos, May 23rd, 2009
38. Aroid-L mailing list, Julius Boos, August 20th, 2006
39. Aroid-L mailing list, Seán A. O'Hara, June 24th, 2004
Additional photos by Bart Jeurninck