Taxonomic name: Tradescantia spathacea Sw.
Synonyms: Rhoeo discolor Hance ex Walp, Rhoeo spathacea (Sw.) Stear, Rhoeo discolor (L'Hér.) Hance, Rhoeo spathacea (Sw.) Stearn, Rhoeo spathacea (Sw.) Stearn forma concolor (Baker) Stehle, Rhoeo spathacea (Sw.) Stearn forma variegata (Hook) Stehle, Tradescantia discolor L'Hér., Tradescantia discolor L'Hér., Tradescantia discolor L'Hér. var. concolor Baker, Tradescantia discolor L'Hér. var. variegata Hook.
Common names: boat lily (English), boat plant (English), faina kula (Tonga), moses in a boat (English), Moses-in-a-basket (English-Hawaii), oyster plant (English), riri mangio (Cook Islands), riri raei (Cook Islands), talotalo, laupapaki (Niue)
Organism type: herb
Tradescantia spathacea is a beautiful succulent that has been introduced to south Asia and many Pacific Islands from its native range in the tropical Americas. Although it has not yet been declared a pest, in many areas it has become a very invasive weed, especially in Florida where it invades and disrupts native plant communities. Tradescantia spathacea creates a dense groundcover on the forest floor which prevents native plants from germinating. Tradescantia spathacea has diverse reproductive methods and grows in areas other plants cannot. These two characteristics make this plant a potential danger to many areas. Monitoring is recommended wherever this species is present.
"Rosette-forming succulent herb, stems short, leaves crowded, elongate, broadly linear-lanceolate, up to 30-40cm long and 4-6cm wide, the upper surface green, the lower surface rich reddish-purple; inflorescence axillary, short; bracts subsessile, boat-shaped; flowers white; petals 3; stamens 6, ovary 3-celled, cells 1-ovulate; fruit capsular 3-valved; seeds rugose" (Stone, 1970. in PIER, 2002).
natural forests, urban areas
Prefers well-drained sites and will grow well on rocks (PIER, 2002). Although it likes soil with substantial organic matter, oysterplant will grow in sand or even coral rock (Floridata.com). It is drought resistant, Likes shade and will invade the forest understory (PIER, 2002).
Can create a dense groundcover that prevents native plants from germinating on the forest floor. (Floridata.com)
Primarily grown for bedding, rock gardens, and tropical effects. The reddening effect of the irritating juice has been used for cheek colouring also, (Floridata.com). The flower is used medicinally for the treatment of dysentery, enterorrhagia and hemoptysis (Brach).
Widely planted as an ornamental, often in cemetaries (PIER, 2002). The sap may cause brief stinging and itching of the skin to some people, and when eaten, oysterplant will cause severe burning pain in the mouth and throat. Relatively tolerant of the allelopathic chemicals (compounds that prevent other plants from growing) put out by Australian pine (Floridata.com).
Native range: Tropical and subtropical Americas.
Known introduced range: American Samoa, Cocos Islands, Commonwealth of the Northern Mariana Islands, Cook Islands, Federated States of Micronesia, outer Caroline Islands, Fiji, French Polynesia, Guam, Hawai‘i, Kiribati, Marshall Islands, New Caledonia, Nauru, Niue, Palau, Samoa, Tonga, Wake Island, Christmas Island, China.
Local dispersal methods
Garden escape/garden waste: Discarded garden waste. Commonly planted (often in cemeteries) and escaping in Tonga. (PIER, 2002).
Horticulture (local): Has escaped cultivation in Florida and Louisiana. Broken pieces resprout easily. (Floridata.com)
On animals (local): Seeds are perhaps wind dispersed. (Center for Aquatic and Invasive Plants, 2000)
Other (local): Spreads primarily by vegetative offshoots where planted. (Center for Aquatic and Invasive Plants, 2000)
Preventative measures: Plant cuttings should not be dumped anywhere as this is a frequent source of new weed infestations. The origin of new top soil or fill should be checked as physical transportation of plant segments in soil is a major method of spread.
T. spathacea can reproduce by seeds, cuttings, and discarded plants (PIER, 2002). Broken pieces will resprout easily (Floridata.com). Tradescantia spathacea flowers all year round, and is pollinated by insects, or self-pollinated (Center for Aquatic and Invasive Plants, 2000).
Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG)
Last Modified: Thursday, 23 March 2006