what are the plants that were introduced on the aforementioned island?
Invasive weed species such prickly sow-thistle, smooth sow-thistle, smooth hawksbeard, scrambling fumitory, green field speedwell, groundsel and nutgrass.
Tristan da Cunha
The majority of invasive weed species that has been introduced to the island are spread by seed and cover 50% of arable land in widely distributed patches. These species include prickly sow-thistle ("Sonchus asper"), smooth sow-thistle ("Sonchus oleraceus"), smooth hawksbeard ("Crepis capillaris"), scrambling fumitory ("Fumaria muralis"), green field speedwell ("Veronica agrestis"), groundsel ("Senecio vulgaris"), and nutgrass ("Cyperus esculentus"). Other invasive weed species that have a more localized distribution in plots include prickly sow-thistle ("Sonchus asper"), smooth sow-thistle ("Sonchus oleraceus"), smooth hawksbeard ("Crepis capillaris"), and groundsel ("Senecio vulgaris"). 
where is the most isolated island on earth Tristan da Cunha, is in the south Atlantic Ocean, lying approximately off the coast of Cape Town in South Africa, from Saint Helena and off the coast of the Falkland Islands. who discovered it? A Portuguese explorer, Tristão da Cunha. who was th explorer? He was a naval commander who served as ambassador from King Manuel I of Portugal to Pope Leo X, leading a luxurious embassy presenting in Rome the new conquests of Portugal. He later became a member of the Portuguese privy council. describe the economical aspects of the island? The island has a unique social and economic structure in which all resident families farm and all land is communally owned. Outsiders are prohibited from buying land or settling on Tristan. Besides subsistence agriculture, major industries are commercial fishing and government. what kind of holidays are celebrated over there? The island holds an annual break from government and factory work which begins before Christmas and lasts for three weeks. The beginning of the holiday, called Break-Up Day, is usually marked with parties and celebrations. name a few plants native to the place? Eudicots and Commelinids are some of them. describe the former plant? They are a clade of flowering plants mainly characterized by having two seed leaves upon germination. who is the first person to describe it? The botanical terms were introduced in 1991 by evolutionary botanist James A. Doyle and paleobotanist Carol L. Hotton. tell me more about the former botanist? UNANSWERABLE
wiki:19591996
Tristan da Cunha [SEP] Introduced plants
Introduced vegetation has altered long-term carbon storage as well as the reduction of CO in the atmosphere. Native plants such as fern bushes, "Phylica" bushes, fern brakes, mires, and bogs, contain high organic content matter which functions as storage for carbon. With the introduction of harmful species, the islands will see a decrease in carbon storage of both the soil and vegetation. With multiple changes occurring within the soil due to invasive plant species, the nutrient cycle is bound to be negatively influenced. Invasive plants are also affecting the human population of Tristan da Cunha by being disease carriers and becoming agricultural pests in gardens and pastures.