10 AROIDEANA, Vol. 22 Observations on Amorphophallus titanum (Becc.) Becc. ex Arcangeli in the Forest of Sumatra

Dr. Cristiana Giordano Dipartimento di Biologia Vegetale, Universita di Firenze, via la Pira 4, 1-50121 Firenze, Italy

ABSTRACT but a different fate was in store for the On the occasion of the centenary of the Kew specimen: after no less than a decade death of Odoardo Beccari the Botanical (1889 vol. IV p. 19) it flowered in captivity Garden of Florence organised two expe­ for the first time. Since then Amorpbo­ ditions in Sumatra (in September 1994 and pballus titanum has flowered many times in many botanical gardens, but never in 1995) to study Amorphopballus titanum in nature and bring it to Florence to try to Italy. grow it. In the course of the two expedi­ On the occasion of the centenary of the tions eight inflorescences and four infruc­ death of Odoardo Beccari the Botanical tescences were found. The inflorescences Garden of Florence decided to resume re­ were at various stages of development and search on this spectacular plant. Two ex­ it was possible to sketch a general outline peditions were organized (in September of the flowering process. We will give a 1994 and 1995) to study the plant in nature detailed description only of the specimen and bring it once again to Florence to try which we observed minute by minute as to grow it. its blossomed. For the others we will just list the most significant characteristics. Morphological Characteristics of AmorpbopbaUus titanum INTRODUCTION As is well known, Amorpbopballus ti­ Amorpbopballus titanum (Becc.) Becc. tanum is a seasonally dormant perennial ex Arcangeli is a herbaceous plant with a monocotyledon. The underground tuber is big leaf resembling the foliage of a tree subspherical depressed-globose and varies and a petiole that looks like a trunk; it can in dimension according to the age of the reach a maximum height of 6 meters. This plant: it can reach 80 cm in diameter and plant produces the biggest unbranched in­ can weigh up to 70 kg. The petiole is florescence in the world: it can grow up smooth and green, covered with whitish to 2.5 meters in height (Camp, 1937). spots, and can reach the remarkable size The Florentine naturalist Odoardo Bec­ of 6 m in height and 30 cm in diameter at cari, who explored the Indonesian forests the base. The leaf is dark green, pinnati­ for many years, in search of new and in­ sect, with ovate or oblong acuminate teresting plant and animal species to study membranous segments, that can grow to (Faenzi, 1878; Beccari, 1878), discovered half a meter in length and about 15 cm in Amorpbopballus titanum in 1878. Beccari width. sent tubers and seeds to Italy but the tu­ The solitary inflorescence of A. titanum bers were held at Marseilles customs and is comprised of a short peduncle (about never arrived. The seeds, however, ger­ 40-50 cm in length and 10 cm in diameter) minated, and the following year the little of the same color as the petiole, and cul­ tubers were sent to various botanical gar­ minates in an enormous spathe whence dens throughout Europe, including Kew emerges the spadix (Fig. 1). The spathe, Gardens in London. which measures about 1.6 m in height and Unfortunately all the plants in Italy died, about 3 m in circumference, has a wide- CRISTIANA GIO RDANO, 1999 11

Fig. 1. Inflorescence of Amorphophallus Fig. 2. Opened inflorescence. titanum in the forest of Sumatra (175 cm tall). cm. The female fl owers occupy the lower two thirds of the space, while the male fl owers take up the upper third (Fig. 2) . open upper part and is closely ruffled When fl owering is over, the stem of the from the lower third to the edge, which is spadix is the first to wither, followed by roughly cut into by short-tipped teeth (Fig. the spathe, which twists on itself, probably 1). At the base it is very light green, with sealing the chamber so as to keep the pol­ the characte ristic w hite spots, turning linated fl owers dry. whitish towards the stiff, thick folds of the It has not yet been established how long aperture at the top. Inside the spathe the Am.orphophallus titanum. takes to flower; purplish wine-red color of the upper edge we know only that the plant which gradually lightens until towards the base it bloomed at Kew in 1889, the only speci­ turns yellow with marble-pink venations men which has been studied from Becca­ (Fig. 2) . ri's seed, took 10 years. Plants grown in From this base a sessile spadix extends botanical gardens have never been known which can reach 1.5 m in the largest in­ to fl ower more than once. After this ex­ dividuals. In the immature fl owers it is hausting effort they all die within a short green, turning yellow or purple towards time, even though at Kew Garden in 1890 the top, and in the mature fl owers it goes (Anonymous, 1890), and in Hamburg in from purple with yellow spots to yellow­ 1929 (Winkler, 1931), the tuber produced orange. It feels velvety and if touched be­ one last leaf the year after fl owering, and comes shiny. At the base of that structure then died. are the reproductive organs, hidden in the Seed reproduction seems to be the only vase formed by the lower part of the certain method. Even though after flow­ spathe; they take up a length of about 25 ering adventitious buds appear on a part 12 AROIDEANA, Vol. 22 of the tuber, a new plant has never been variation is remarkably wide: the day can known to grow from these budS, .and the be almost 10 degrees Celsius warmer than many attempts at vegetative propagation the night. Under a thin layer of humus the made with these budS have all met with soil is sandy and quite loamy. In the area failure (Camp, 1937). in which we found the inflorescence and the vegetative part there are no active vol­ FIELD OBSERVATIONS canoes; but the soil is made up of an ex­ panseof andesitic and rhyolitic lava, and The vegetative part, unlike the inflores­ dacitic and rhyolitic tuff (Dr. Guderson, cence, is almost common in certain parts 1995, pers. comm.). of. the island. We came across it not only Amorphophallus titanum in flower has in Ajer Mantcior, where Beccari first dis­ been found also in secondary forests, covered it (Beccari, 1930), but also in three where the spontaneous vegetation is in­ other areas: in the center of Sumatra in the terspersed with trees grown for food and north~western part of the island, and in the for trade, Hevea brasiliensis in particular. hinterland of Padang province. These ar­ In spite of the density of the vegetation, eas, though far apart, are all marked by the most inflorescences were found in rather same abiotic factors: they are alL between open spaces, where there is almost no un­ 400 and 1,000 meters above sea level, with dergrowth, and where the light is not too a warm humid climate, regular rainfall and direct: often the stations were abandoned wide variation in daily temperature. plantations or cleared forests near a brook. The vegetative part lives in more or less degraded secondary forests that are at Stages of Development points encroached upon by gum tree, fruit tree, and· coffee plantations. The natives In the course of the two expeditions clean up only the part of the forest sur­ eight inflorescences and four infructesc­ rounding the trees they are interested in, ences were found. The inflorescences the result is called by Laumonier "a mosaic were at various stages of development and of degraded vegetation and. plantations" it was possible to sketch a general outline (Loumonier, 1983). of the flowering process. We will give a The plants live in the most varied light detailed description only of the specimen conditions and they emerge· from very which we observed minute by minute as shallow forest undergrowth « 1 m) in the its blossomed. For the others we will just shade of high trunk trees. Although they list the most significant characteristics. seem to prefer half-shade, one can find The youngest specimen-according to them also· in deep shade or in well-lit lo­ our guides it was only a few weeks old, cales. was 116 cm tall (Fig. 3). The spathe, green The plants occur in dusters of varying at the base and white towards the top, was size: sometimes three or four are born at­ spattered with white spots; it was com­ tached with a few others plants in the im­ pletely wrapped around the spadix which mediate vicinity; or various specimens can emerged from it for 30 cm. The appendix be scattered· within a radius of a few me. was green and odorless with a filamentous ters; it is quite rare to find completely iso­ interior. Inside the spathe was red at the lated individuals. base turning green towards the top. The It was very difficult to find plants in purple-brown cataphyll splotched with flower. We found some only in a circum­ white was still. erect at the side of the scribed area of the island, where they are spathe. also rare. The flowering stations- are on The spathe of another bud (174 em tall) steep hills between SOG and 1,200· m was still· closed around the spadix, which above sea level. At this altitude, without was quite- purple, stiff, and folded in prejudice to other characteristics common pleats. The spadix's surface was velvety to the whole island, the .daily temperature and its circumference at the end of the CRISTIANA GIOHDANO, 1999 13

Fig. 3. Youngest specimen , bud 116 cm Fig. 4. Inflorescence opening. tall.

was no smell but if you put your nose to spathe measured 64- cm. Only from very the opening of the calyx you could dis­ close by could you discern a sharp smell tinctly perceive the stench of rotting fl esh. of rotting fl esh. The male flowers had not EvelY minute the smell became more yet emitted poll en and the female flowers and more intense and we supposed that had not yet received it. We found some soon the fl ower would open. We stayed to Coleoptera of the family of Curculionidae observe it the whole day and we did in­ and Hybosoridae beetles, of the latter deed witness an extraordinary spectacle: there were many Phaeochroops emargin­ the inflorescence opened in the space of atus. a few hours before our amazed and won­ The specimen we fo ll owed through me dering eyes, revealing itself in all its splen­ whole duration of the anthesis -was in a dor. relatively pristine secondary forest where We tried to handle it as little as possible gum trees grew sporadically. The inflores­ so as not to affect the unfolding process. cence was on velY steep terrain (its slope The opening of the spathe was measured measured about 50%), fa ced east, and was in 3 places and we saw that it moved away quite shady in spite of a tree which had from spadix at the rate of about 2 cm every just fallen, creating an open, airy space. A fifteen minutes. It continued to do so until few meters downhill was a brook. about 3:30 P.M., when it slowed down; by When we reached the site at 11 :30 A.M . 5:30 P.M. it had reached its maximum ap­ the spathe was about 10 cm away from the erture: 102 cm in diameter (Fig. 1). spadix, its maximum · circumference was Ambient temperature remained steady 130 cm and the whole inflorescence was at 26°c until about 2 P.M. , when it rose to 175 cm tall, 159 cm without the peduncle 27°C. The temperature ofthe inflorescence (Fig. 4). In the immediate vicinity there was taken at regular intervals with a COD- 14 AROlDEANA, Vol. 22

Fig. 5. Phaeochroops emarginatus going out of the cut spathe.

tact thermometer (Emplex Digi Mini) in two places: at the base of the calyx, be­ Fig. 6. Trigona geissleri resting on the tween the spathe and the spadix, and on stigma. the surface of the latter. The base was always one degree cooler than the surrounding environment, while waves and only in certain directions, al­ the temperature of the spadix measured ways emanating from the overlap of the 26°c (ambient temperature) until about 2 spathe and almost always downhill from P.M. when it rose to 28°C--one degree the fl ower, perceptible even several me­ above ambient temperature. Before the in­ ters away. The overlap always faced fl orescence opened the surface tempera­ downhill, southward (this was the case in ture of the male fl owers was found to be the above-mentioned specimen as well), almost two degrees above ambient tem­ and here the stench was almost constant, perature. whereas uphill it was nearly undetectable. The odor became more intense during From the beginning we noticed that the the course of the day, and around 5 same whitish powder we fo und in the in­ o'clock it seemed to change: it now stank fl orescences was present around the in­ of excrement rather than rotting fl esh, the side circle of the spathe in the lower part. same process was noticed in Arum ma­ The appendix was green , shading into culatum by Bermadinger-Stabentheiner & yellow toward the bottom. It folded in on Stabentheiner (Bermadinger-Stabentheiner itself in thick, stiff invaginations. Its maxi­ & Stabentheiner, 1995). The stench was so mum circumference was 62 cm. sharp and suffocating that it was impossi­ As for insects, in the morning w e no­ ble to approach the plant; it came in ticed very few flies, but around 1 P.M. c m STIANA GIO RDANO, 1999 15

Fig. 8. Inflorescence just after the bloom- Fig. 7. Inflorescence just after the bloom- ing. ing.

Eggs had been deposited along the fold that hosted the spide r. swarms of fli es, fruit fli es, and bluebottle There were only a very few insects hov­ fli es began to arrive. Many fli es and Tri­ ering around the spadix, nothing com­ gona bees hovered around the spadix and pared to the swarms of the day before. By fl ew into the inflorescence alighting on the lightly touching the male fl owers we male and female fl owers. found that the po ll en had not yet came out During the night there was a violent of the anthers. thunderstorm, and the morning after it was In the course of the day the appendix still raining. When we returned to the site became yellower and the smell disap­ at 9 A.M., it had not stopped raining and peared almost completely. The appendix we found that the inflorescence had split open very easily under li ght pressure closed in four points, forming four loops from a hard obj ect, and the characteristi c or eyelets. According to the natives, who unpleasant odor wafted out from this fi s­ had came to check on the inflorescence sure. Late in the afternoon the anthers be­ during the night, the spathe had started gan to release poll en. On the morrow we closing only after the beginning of the found that the inflorescence was even storm, around 4 in the morning. more closed, the loops having narrowed. The overpowering stench of the day be­ The spadix had become completely yel­ fore was gone and there was only a bear­ low and quite wrinkled. able scent very close to the appendix, We proceeded to cut the spathe and which had became completely yellow ex­ only then did we discover the animals liv­ cept for the tip. The circumference had not ing at the bottom of the inflorescence: be­ changed and neither had the stiffness. sides a few spiders there was a great num- 16 ARO IOEANA, Vol. 22

Fig. 10. Window cut into the spathe Fig. 9. Inflorescence at a more advanced showing male and female flowers. stage.

low ish droplets. The inner walls of the ber of Coleoptera of the Histeridae and spathe (which had closed aro ~md the spa­ Hybosoridae families: Phaeochroops dix) were wet, and at the bottom there emarginatus (Fig. 5), (which we found was a yell owish liquid. Inside this inflores­ also in Amorphophallus paeonii./ohus) , cence we found Formicidae and a Cole­ and an insect of the Blattaria order. Almost o ptera (Brentidae): Hormocerus compres­ all the beetles were on the bottom of the silarsus. spathe; very few were among the female We found another inflorescence that flowers. Once we removed the spathe a had just opened, but in this one the spathe great number of Trigona geissleri swarmed was close to the spadix and stuck to it in around the plant, and some were seen only a few points (Fig. 8). The spadix was resting on the stigma (Fig. 6). yellow-orange and emitted a strong odor Anothe r inflorescence was found to only if you smell ed it from veIY close by. have completely shut aft er fl owering: the The female fl owers had been pollinated spathe was closed around the spadix, but and pollen was hanging from the male rather than wrapping around the appendix fl owers in thin threads about 1 cm in (as it would in a bud), it narrowed, like a length. bottleneck, at the upper fifth , forming a The appendix of a specimen at a more kind of collar under the top part of the advanced stage was folded over the petal (Fig. 7). Inside, the female fl owers spathe, having lost its rigid structure (Fig. had already been pollinated and the male 9); it was yellow at the apex, turning red flowers had already released the pollen. towards the bottom, with irregular yellow The appendix was yell ow and odorl ess spots where the tissue was decaying; this and had secreted very sticky foamy yel- was the only part which gave out a strong CRISTIANA GIOHDANO, 1999 17

Fig. 12. Inflorescence at the most ad­ vanced stage.

could you see the threads of pollen on them (Fig. 11). The tuber was irregularly shaped, with a maximum circumference of 160 cm; it was 40 cm tall and weighed about 40 kg. Inside the inflorescence we found Cole­ optera: Staphilinidae (already noticed by Jacobson in Van der Pijl L. , 1937) and Scar­ abeidi, and Trigona geissleri.

Fig. 11. Threads of pollen going out of the male fl owers.

putrid smell. The female flowers had been pollinated, and the stigmas were covered with pollen. The infl orescence, which had wilted a few days before, did not give out any odor; only inside the appendix was the smell strong. The spathe, loosely closed around the appendix with a bottle­ neck three quarters of the length up, formed a liver-red crown. Without the ap­ pendix the spathe measured 1.57 m and with the erect spadix it measured 2 m. Through the window cut into the spathe (Fig. 10) we saw that the inside was cov­ ered with a whitish powder and there was a yellowish skin of fungi at the base of the appendix. The ovaries were turgid and wine-red in color. The stamens were per­ fectly preserved and only in one point Fig. 13. Female flowers. 18 ARO IOEA A, Vol. 22

Fig. 14. Infructescence. Fig. 15. Fruits.

The inflorescence that had reached the most advanced stage had wilted at least two weeks before (Fig. 12). The spathe merous and at fructification the to p of the and the spadix were completely rotten and plant resembles a cylinder covered with they covered the part of the appendix that little tomatoes. At the base there are small­ held the fl owers, practically sealing it. The er fruits, some not yet developed, while male flowers , which had maintained their towards the top the fruits were ripe r. original structure, were rotten and brown. When ripe the fruits are 3-4 cm long, red, In contrast, the ovaries of the female fl ow­ smooth, and pulpy; in shape they resem­ ers were turgid and white, turning pink to­ ble olives (Fig. 15). ward the top; the styles were wrinkled and The fruits have a rather large pulpy peri­ dark-purple, almost black, and the white, carp and contain 2-3 seeds, 4-4.5 cm by turning pink toward the top; the styles and 2- 3 cm. They are smooth and black on the the stigmas were wrinkled and dark-pur­ outside; the external face is convex and ple (Fig. 13). Inside the spathe was com­ the inner side is flat or carinate, with a pletely wet. central ridge. The infructescences we found (Fig. 14) Amorphophallus titanum has now been measured 140 cm in height: the 80 cm tall grown in the Botanical Garden of Florence stalk was topped by an upper part, mea­ since 1994. Its fl owering is much longed suring 60 cm. The fruits jut out vertically for event as it has never bloomed in the from this upper part; they are quite nu- city of its discoverer. CRISTIANA GIORDANO, 1999 19

ACKNOWLEDGMENTS tissues in infloresceces of Arum ma­ culatum. New Phytol. 131:41-50. I wish to thank all the people who con­ Blasco, F. 1988. The international vegeta­ tributed to this work: the late Dr. James tion map (Tolouse, France) In A. W. Symon, Prof. Enio Nardi, Prof. Fernando Kunchler, 1. S. Zonneveld (eds.), Fabbri, Drs.Wilbert Hetterscheid for the "Vegetation mapping." Handbook of valuable advice and Dr. H. Huijbregts (The Vegetation Science n. 10. Kluwer Ac­ Netherlands) for identifying the insects. ademic Pub!., Doordrecht. Camp, W. H. 1937. Notes on the physiol­ UTERATURE CITED ogy and morphology of Amorpho­ phallus titanum. J. N. Y. Bot. Card. Anon. 1889. Amorphophallus titanum. 38:190-197. Card. Chron. VI:19-20. Fenzi, E. O. 1878. Una pianta meravigliosa. --. 1890. Amorphophallus titanum. Bull. R. Soc. Tosc. di Orticult. III:270- Card. Chron. VII:330. 271. Beccari, N. 1930. Odoardo Beccari in Su­ Laumonier, Y. 1983. International Map of matra e la scoperta dell' Amorpho­ the Vegetation at 1/1.000.000 Scale, phallus titanum. Boll. R. Soc. Ceo. "Sumatra". Biotrop. Bogor Indone­ Ital. VII:569-595. sia. Cited in Blasco 1988. Beccari, o. 1878. II Conophallus titanum Van der Pijl, 1. 1937. Biological and phi­ Beccari. Bull. R. Soc. Tosc. di Orticult. siological observations on the inflo­ III: 290-293. rescence of A morphophallus. Rec. --. 1889. Fiori dell'Amorphophallus Trav. Bot. Neer. 34:157-167. titanum. Bull. R. Soc. Tosc. di Orti­ Winkler, H. 1931. Einige Bemerkungen tiber cult. XIV:250-255. Mangrove-Pflanzen und den Amor­ Bermadinger-Stabentheiner, E. & A. Sta­ phophallus titanum in Hamburger bentheiner. 1995. Dynamics of ther­ Botanischen Garten. Ber. Deutsch mogenesis and structure of epidermal Bot., Ces. 49:87-102.