NOTES ON Amydrium zippelianum (ARACEAE): A MESMERIZING SPECIES FROM EAST MALESIA

Amydrium zippelianum (Araceae) was reportedly found in Malesia, from Sulawesi to Papua New Guinea, but it is rarely seen now. Flora exploration has been conducted to reveal flora diversity in Banggai Kepulauan Regency, a group of small islands in Central Sulawesi Province. This study was aimed to find and collect A. zippelianum specimen. Flora exploration was carried out by applying taxonomy data collecting method in Peleng and Bakalan islands, Banggai Kepulauan Regency. Plant materials were collected for herbarium specimens and deposited in Herbarium Bogoriense (BO). The specimens of A. zippelianum deposited in BO and online portal database were further examined. In addition, observations of herbarium specimens were also done to obtain more information about A. zippelianum in Malesia. A distribution map was provided and data were analyzed descriptively. One fertile specimen of A. zippelianum was successfully collected around Kokolomboy Forest, Banggai Kepulauan Regency. In Malesia, A. zippelianum can be found in lowlands to highlands at elevation up to 2,200 m asl and mostly in forest area. The distribution of this species in nature covers Sulawesi, Maluku, Papua New Guinea, and the Philippines. This plant was introduced to Java (Bogor Botanic Garden), Bali (“Eka Karya” Bali Botanic Garden), and United Kingdom (Royal Botanic Garden, Kew).

Amydrium zippelianum is easily recognized by the blade of leaves that is rather big, deeply laciniated, ovate-cordate in outline, up to 125x90 cm; spathe that is yellow and deciduous, fruit that turns red when mature (Nicolson, 1968). This species is possibly confused with a similar species: Epipremnum pinnatum (L.) Engl. The most easily observed distinguishing feature concerns the petiolar sheath, where A. zippelianum has sheath that reaches only to the top of the basal geniculum, while in E. pinnatum, the sheath is extending to half way along the apical geniculum (Boyce, 2004). The leaf pattern of A. zippelianum is very beautiful and potential to be ornamental plant (Yuzammi, 2018), indeed, their flower and fruit are also magnificent. Amydrium zippelianum is a huge climber aroid occurring in the east part of Malesia from Sulawesi, Maluku, and the Philippines to Papua New Guinea (Boyce, 1995). This species is also found in the small islands around mainland of Sulawesi, such as Talaud Islands (Dzu, 2003).
Amydrium zippelianum is commonly found and grows scattered in flat bank forest. It has an economical value as medicinal and ornamental plant. However, there is not enough information about its conservation status due to limited exploration data. Although it was reported as a common species, A. zippelianum was rarely found during the flora exploration (Araceae in particular). There is no record of this species in Talaud Islands exploration that was conducted by author (Ina Erlinawati) Sulawesi, Erlinawati (2010) reported the diversity of terrestrial Araceae only. Therefore, there is no sufficient record of climber aroids and it seems that A. zippelianum is rarely found now.
The total number of A. zippelianum specimens deposited in BO reaches 38 numbers, while 17 numbers were deposited in another herbarium. Most of the specimens were mainly collected from mainland of Sulawesi and there is no record from the surrounding small islands. Therefore, the exploration in the small island is necessarily done to obtain more information about this species. Banggai Kepulauan Regency is a group of small islands around mainland of Sulawesi that belongs to Central Sulawesi Province. It is an archipelago with 2,488.79 km 2 of a total land area and 6,671.32 km 2 of sea area (Badan Pusat Statistik Kabupaten Banggai Kepulauan, 2018). The islands are located in the south of the eastern peninsula of Sulawesi with an altitude of 0-1,000 m. The largest island is Peleng (it is pronounced as "Peling") (Badan Pengelolaan Lingkungan Hidup Kabupaten Banggai Kepulauan, 2009) covering area of 2,325 km 2 (Hasanah, 2017). Despite its status as developing region, the local people in this area have not yet optimized the forest resource due to limited information about its biodiversity. Hence, A. zippelianum is less recognized and not well utilized.
Flora and fauna exploration has been carried out by Rahmadi et al. (2014) in Banggai Kepulauan Regency. However, specimen of Amydrium species was not found during this exploration (Rahmadi et al., 2014) even though this area is its natural distribution. Recently, we re-conducted flora exploration in Banggai Kepulauan to reveal more species diversity of this location. This activity was aimed to find and collect A. zippelianum specimen from Banggai Kepulauan Regency. The results of this study were presented in this paper. In addition, observations of herbarium specimens were also carried out and aimed to obtain more information regarding the existence of A. zippelianum species in Malesia.

MATERIALS AND METHODS
This study was conducted through flora exploration and herbarium specimen examination. Flora exploration was carried out by applying taxonomy data collecting method according to Rugayah, Retnowati, Windadri, and Hidayat (2004) from June to July 2019 in Peleng and Bakalan islands, Banggai Kepulauan Regency, Central Sulawesi Province (Figure 1). Sample of plant materials (leaves, flower, and fruit) were collected for herbarium specimens. Data of habitat, location, coordinates, and the altitude of the samples were also recorded. Photographs of fresh specimens were also taken. The herbarium specimens were sent to the Herbarium Bogoriense (BO) to be further processed (Djarwaningsih, Sunarti, & Kramadibrata, 2002) and deposited. The specimens were identified through literatures written by Boyce (1995), Dzu and Boyce (1999), Dzu (2003), Boyce and Wong (2015), and also by matching the specimens found with BO specimens and online specimen photographs. The herbarium specimens of A. zippelianum deposited at BO and portal online databases were examined. A distribution map was made by using R software version 6.3.2. Coordinates were compiled from the data of BO specimens and other digital specimens that were available at portal online databases such as Jstor, GBIF, and POWO (see Jstor, 2020;Global Biodiversity Information Facility, 2020; Plant of the World Online, 2020). The areas without coordinates (just the name of the area) were fixed by using Google Maps. Eventually, data were analyzed descriptively.

RESULTS
Exploration conducted in all locations resulted in only one fertile specimen [I. P. G.

P. Damayanto & A. Haryadi 934 (BO)] of A.
zippelianum found from one individual mature plant in the shady and rather open areas around the forest of Kokolomboy, Banggai Kepulauan Regency at an altitude of 500 m. Specimen was added to the Araceae collection in the BO, especially as Sulawesi region collection. Eventually, this addition changed the total number of Malesia collection in BO to 39 numbers. Meanwhile, 103 sheets out of 56 collection numbers of A. zippelianum specimens have been observed (Table 1). This species can be found in lowlands to highlands at elevation of 3-2,200 m asl. Most of them (87.5%) were categorized as fertile collections (with flower or fruit) and widely found in forest areas. Specimen collections were mostly abundant in Sulawesi (34%), followed by Maluku (30%), Papua New Guinea (23%), Philippines (9%), and Java (4%). Specimens from Java are the cultivated species collected from Papua New Guinea. The oldest specimens were collected in 1906 and the newest was discovered in 2019. Most specimens were deposited in herbaria of BO and Naturalis Biodiversity Centre (L). Description. Low climber. Main stems prostrate or climbing, 2.5-3 cm thick, internodes 2-5 cm long, roots usually appear from stem nodes. Leaves blade 75-100x65-80 cm, ovate-cordate in outline, pinnatisect often to the midrib, shiny green above and shiny pale green below. Sheath 7-8 cm long, not exceeding lower geniculum. Petioles 40-60 cm long, green, channelled apically. Peduncle 10-20 cm long, erect but sometimes spreading. Spathe broadly ovate, 9-10x8-10 cm long, reflexing at anthesis, turning green into yellow and finally deciduous. Spadix 5-6x3-4 cm, yellow when anthesis and turning orange-red when mature. Flowers arranged in a honeycomb pattern, bisexual; stamens 4. Infructescence cylindrical, 14-20x2-5 cm, yellow then turning orange-red when mature; seed 1.1x0.6x0.5 cm, brown to black, smooth, one seed per locule, locules two.
Conservation status. The information about the population of this species is not available. Conservation status of this species, therefore, is not evaluated. Based on some collector's notes, this species is relatively common in the forest of Papua New Guinea and Talaud Islands, Sulawesi. Moreover, according to Boyce (1995) this species is occasionally found in regrowth forest or as a weed in plantations. Unfortunately, author (Ina Erlinawati) did not find this species during aroid exploration in Talaud Islands in 2017.

Ecology and Distribution
Nicolson (1968), Boyce (1995), andDzu (2003) mentioned that A. zippelianum can only be found at elevation up to 1,800 m asl. Moreover, the result of this study showed that this species could grow in lowlands to highlands at altitude of 0-2,200 m asl ( Figure  3). The boxplot in Figure 3 shows the distribution of A. zippelianum in regard to the elevation where Malesia obtained maximum elevation. In this case, species occurrence in Malesia obtained lower median elevation compared to that in Maluku islands despite the similar range of elevation in area where the species was found. This result is possible since less exploration was conducted in Maluku Island, especially at a higher elevation. In addition, similar results of median elevation were shown in other locations, revealing this species is mainly found at lower elevation. This finding is in accordance with the other reports of A. zippelianum confirming the species is mostly found in primary forest, from lowland to lower mountain rainforest.
Plants have the adaptability to adjust to the expression of their morphological and physiological traits in response to environmental variations (Sultan, 1995;Robakowski, Montpied, & Dreyer, 2003;McIntyre, Lavorel, Landsberg, & Forbes, 2009). Altitude can significantly influence plant growth, structure, function, and metabolism (Berli, Alonso, Bressan-Smith, & Bottini, 2013;Dogra, Ahuja, & Sreenivasulu, 2013). At present, studies about the morphological changes as adaptation mechanism of A. zippelianum in relation to altitude variation is largely unknown and inadequate. However, some trees such as alpine plants show specific morphological, physiological, and biochemical responses as altitude increases followed by lower temperature, i.e. small leaf size and thickness increases (Richardson, Berlyn, & Gregoire, 2001;Guo, Li, & Zhang, 2016). Those morphological changes lead to highly efficient leaves with respect to photosynthesis (Korner & Diemer, 1987). The fact that cell size is not reduced at high altitudes indicating that mountain plants and their respective organs are small for producing fewer cells (Korner, Neumayer, Menendez-Riedl, & Smeets-Scheel, 1989). Renner, the Director of Munich Botanic Garden, mentioned that they do not have A. zippelianum in cultivation. Moreover, based on personal communication in 2020 with Roxana Glenn, a staff of the visitor information field of Royal Botanic Garden, Kew, there is one living collection of A. zippelianum in Princess of Wales Conservatory, a glassy house dedicated to carnivorous plant, succulent species, and some tropical plants. Amydrium zippelianum in those botanic gardens were reported flowering and fruiting regularly (Boyce, 1995). Based on data of herbarium specimens, A. zippelianum in nature can be found producing flowers and fruit throughout the year ( Figure 5). Flowering and fruiting season of this plant in natural habitat most frequently occurs from May to June. It was observed that the end of the dry season in tropical area is the time when most plants produce fruit.