Invasive Alien Species

Species Name: Alternanthera philoxeroides

Family Name:
Amaranthaceae
Synonym:
Althernanthera philoxeroides (Mart.) Moq.
Bucholzia philoxeroides Mart.
Telanthera philoxeroides Moq.-Trand.
Origin:
Tropical South America
Description:
Perennial herb, with creeping or floating stems, the end ascending or erect, often strongly branched, 50-100 cm tall.  Stem hollow; internodes on 2 opposite sides with a hairy groove; petiole 3-6 mm long. Leaves opposite, glabrous, entire, oblong to oblong obovate, 2.5-8 x 0.3-0.5 cm. Inflorescence usually axillary and peduncled, sometimes solitary, terminal sessile head; heads ovoid to globose or ellipsoid, 0.8-1.5 cm long; peduncle1-4.5 cm long or shorter; bracts and bracteoles white, one nerved, persistent; bracts ovate-triangular, 2-2.5 mm long, bracteole ovate, very acute, 2.3-2.5 mm long; flower bisexual, almost sessile; tepals 5, oblong, one nerve, 5-7 mm long, often unequal. Stamen 5; filaments 3-4 mm long; ovary superior; style short, thick, stima one, small.  Fruit is unknown in Malesia
Invaded Habitat:
Stagnant or slow-moving fresh water, pools and ditches; tidal and lebak rice fields. Dense floating mats in ponds and canals interfering with the flow of water.
Distribution:
In 1875   observed for the first time in Jakarta, naturalized in  Java ,  and spread to Sumatra, Kalimantan and Nusa Tenggara.
Ecology:
Often it grows in association with other aquatic weeds such as water hyacinth and water lettuce. During the low water it covers the muddy bank and low-lands. As terrestrial plant, its root system and top growth is much different than those in floating or emerged plants
The plant grows best in eutrophic conditions and can grow either as a floating aquatic plant or terrestial.  It forms dense mats as a result of vegetative growth and proliferates rapidly under favorable conditions.  A single plant can cover several square metres, and infestations impair water flow and crowd out native species.  The plant is salt-tolerant and can adapt to low light conditions, e.g. up to 12 % of full light.
References:
  1. Backer , C. A. & R. C. Bakhuizen Van Den Brink.  1965.  Flora of Java Vol I. N.V. P. Noordhoff. Groningen, Netherlands. 
  2. Budiman, A., M. Thamrin and S. Asikin.  1988.   Beberapa Jenis Gulma di Lahan Pasang Surut Kalimantan Selatan dan Tengah dengan Tingkat Kemasaman Tanah Yang Berbeda.  Dalam Prosiding Konferensi HIGI IX. 
  3. Miyaura, Rie.  2001.  Weed Distribution and Its Control in Highland Indonesia : The Case of West Java and Bali.  In Highland Vegetable Cultivation in Indonesia, A Multi-Disciplinary Study toward Eco-Eco Farming.  Tokyo, Japan.  
  4. Pancho, J. V. and M. Soerjani. 1978. Aquatic Weeds of Southeast Asia. Univ. of the Philippines at Los Banos and SEAMEO BIOTROP, Bogor.
  5. Soerjani, M., A. J. G. H. Kostermans & Gembong Tjitrosoepomo (Eds.).  1987.  Weeds of Rice in Indonesia. Balai Pustaka. Jakarta
  6. Weber, E.  2003.  Invasive Plant Species of the World.  A Reference Guide to Environmental Weeds.  CAB International Publishing.