FIRST RECORD OF NATURALIZED ACMELLA BRACHYGLOSSA AND ACMELLA RADICANS (ASTERACEAE: HELIANTHEAE) IN JAVA, INDONESIA

West Java (Bandung Regency, Bandung City, Sumedang Regency) and Central Java (Temanggung Regency). Descrip-tions, illustrations, a key to Acmella of Java, and a brief discussion are presented in this paper.

Human activities can move a plant species across the border of its native distribution, such as a plant called an introduced or alien plant species. According to Pyšek et al. (2004), naturalization is the process by which introduced plants sustain selfreplacing populations for at least ten years without any human interventions. They can grow independently in their new distributional areas by seeds or ramets (tillers, tubers, bulbs, fragments) (Pyšek et al. 2004). Previous studies revealed that 13,168 plant species have become naturalized worldwide (van Kleunen et al. 2015;Pyšek et al. 2017). As many as 878 introduced plants are found in Malesia, and 467 species have naturalized in the region (Holmes et al. 2022). The three largest naturalized groups in Malesia are Fabaceae (171 species), Poaceae (160 species), and Asteraceae (103 Species) (Holmes et al. 2022).
Asteraceae is one of the significant contributors to the naturalized flora in the world (Wu & Wang 2005). It comprises 600-1700 genera and 24,000-30,000 species distributed globally, except in the Antarctic (Funk et al. 2009;Hind 2015). Tropical America was recorded as the critical origin of naturalized species of Asteraceae, followed by Europe and temperate America. Several newly naturalized Asteraceae have been reported from Malesia in the last five years, for example, Praxelis clematidea R.M.King & H.Rob., Tilesia baccata (L.) Pruski and Wollastonia asperrima Decne (Chen et al. 2018;Tjitrosoedirdjo & Wahyuni 2018;Middleton et al. 2022). In this study, we formally report two newly naturalized species in Java, Indonesia, Acmella brachyglossa Cass. and A. radicans (Jacq.) R.K.Jansen. The occurrence of both species has not mentioned by Koster & Philipson (1950), Backer &Bakhuizen van den Brink (1965), andJansen (1985).
According to the previous studies, five species of Acmella occurred in Java, namely A. calva (DC.) R.K.Jansen, A. grandiflora (Turcz.) R.K.Jansen., A. oleracea (L.) R.K.Jansen, A. paniculata (Wall. ex DC.) R.K.Jansen, and A. uliginosa (Sw.) Cass (Koster & Philipson 1950;Backer & Bakhuizen van den Brink 1965;Jansen 1985). Most of them are naturalized species from America, while A. grandiflora is native to Vietnam, Java, the Philippines, and Papua New Guinea (Jansen 1985). Our finding increases the number of Acmella in Java into seven species. A key to the species in Java, the colour photographs of A. brachyglossa and A. radicans, and a brief discussion are provided.
Specimen observations were carried out in the Herbarium Bandungense (FIPIA).  Figure 1.
In this study, A. brachyglossa and A. radicans are newly recorded alien species in Java. The occurrences of these species were not recorded by Jansen (1981Jansen ( , 1985, Koster & Philipson (1950), and Backer & Bakhuizen van den Brink (1965). The history of their introduction to Java is not known. We assumed these species might be unintentionally introduced to the island as soil contaminants. Their occurrence in Java has only been recorded and reported, although it may have been introduced long ago. Acmella brachyglossa and A. radicans were naturalized in several locations in Java ( Figure 3) and like to grow in open areas with direct sunlight. Acmella brachyglossa was found growing along the side of Jl. Nasional V in Sumedang Regency at 518 m elevation. Acmella radicans has more encounters in West Java (Bandung Regency, Bandung City, and Sumedang Regency) and Central Java (Temanggung Regency). It has been naturalized in agricultural fields, gardens, sidewalks, and roadsides at 518 to 722 m elevation. Acmella brachyglossa is native to Central America, South America, and the West Indies (Jansen 1985;POWO 2022). The species are also reported to have become naturalized in Taiwan (Chung et al. 2008) and Thailand (Panyadee & Inta 2022) ( Figure 4A). The other species, A. radicans, is distributed from Mexico, Central America, to Colombia (POWO 2022) ( Figure 4B). The introduced population is also common in Cuba, Curacao, and Tanzania (Jansen 1985). Currently, A. radicans has spread to several tropical countries (Hyde et al. 2022), including India (Bhowmik et al. 2013;Maity et al. 2017;Bagga & Deshmukh 2018), Bangladesh (Rahman et al. 2016), and Thailand (Jansen 1985;Panyadee & Inta 2022). In their native area, both species are found in disturbed habitats along roadsides, streambanks, fields, and pastures. They are expected to become stubborn weeds outside their natural range (Jansen 1985;Chung et al. 2008;Maity et al. 2017;Panyadee & Inta 2022). Acmella brachyglossa can be mistakenly identified with other species from its leaf morphology (Chiu & Chang 1998;Chung et al. 2008). Morphologically, A. brachyglossa has pale yellow or greenish heads and inconspicuous ray florets. Other species with radiate heads, such as A. ciliata and A. uliginosa, have yellow or orange-yellow heads. Moreover, the achenes of A. brachyglossa are densely ciliate without a cork-like edge (Panyadee & Inta 2022). They also have a well-developed pappus of 3 or 2 subequal bristles, which is especially valuable for identification in dried specimens. Acmella radicans is characterized by their white discoid heads. The white florets are clustered in an axillary or terminal inflorescence consisting of 2-3 heads and are solely 4-merous in symmetry (Panyadee & Inta 2022).
Acmella brachyglossa and A. radicans are annual plants that can produce flowers throughout the year (Jansen 1985). Both species can spread rapidly in Java due to the bristly pappus on their achenes (Fig. 1F & 2G). Pappus facilitates the seeds to be dispersed by wind, water, or attached to animals and humans. The seeds are also dispersed as a contaminant in soil, crops, and agricultural machines. These mechanisms can be observed in other species, such as A. paniculata and A. uliginosa (Sw.) Cass. (Soerjani et al. 1987;Chung et al. 2007).
In general, the species of Acmella, including A. brachyglossa, are known as jotang by the Sundanese ethnic community in West Java. The plant is often eaten as a raw vegetable (lalab) and as toothache medicine. This utilization also occurs in other Asian countries. A. brachyglossa has been cultivated for over a decade by Taiwanese folk herbalists as a medicinal plant to treat curvy, toothache, throat and gum infections (Chung et al. 2008). In Thailand, A. brachyglossa and A. radicans are eaten raw as a vegetable and commonly sold in the traditional markets with other species of Acmella (Panyadee & Inta 2022).