Updated and rewritten May 2, 2006 at 10:45am PST to incorporate the proper identification of this plant by Douglas Justice (see comments below).
Commonly known as giant rhubarb or Chilean rhubarb, Gunnera tinctoria, is earmarked as a potentially invasive plant in New Zealand. Carol Ja, a member of the UBC Forums, posted in this thread about a report from New Zealand examining this exotic species: Williams, PA et al. 2005. The identity of Gunnera manicata Linden ex André – resolving a Brazilian-Colombian enigma. Taxon. 51(3):493-497). Thought to have the largest leaves of all Gunnera species, a cultivated plant in Ireland had leaves that measured 3.4m (11ft) in width – all from one growing season (via Wikipedia’s entry on Gunnera)
Flickr BPotD Group Pool Pics of the Day: more photographs of today’s plant, Gunnera
chilensis tinctoria 1 and Gunnera chilensis tinctoria 2, photographed in San Francisco’s Strybing Arboretum by EricinSF@Flickr (note: see Douglas Justice’s comments below re: synonymy of Gunnera tinctoria and Gunnera chilensis).
Photography / biology resource link: BioMedia (particularly the galleries) provides photographic glimpses into the lives of creatures not usually seen with the naked eye. Photographs are often accompanied by short, informative essays.