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 metres 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
STORY:
STORY TITLE: The only one they found
Every titan arum alive today is descended, more or less, from one plant that Odoardo Beccari saw flowering in Sumatra on 5 September 1878.
He had come upon the species a month earlier, on 6 August, 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.
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.
4. Aroideana 19 (1996):P7 - 131
5. iNaturalist: Amorphophallus titanum
6. Das Pflanzenreich IV.23C (Araceae-Lasioideae): 86-87 (1911)
Additional photos by Bart Jeurninck