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.