PHOTOGRAPHED AT THE BOTANIC GARDENS IN DUBLIN
Within the living collections at the National Botanic Gardens they have over 300 endangered species from around the world, and six species already extinct in the wild. These are a vital resource, like a Noah’s Ark for the future. Cultivating a wide range of plants from the diverse climatic regions of the world, and displaying these under good horticultural practice allows visitors to see what they too can achieve in their own gardens. They run training courses in gardening and hold practical workshops throughout the year.
The Gardens are open every day throughout the year except for Christmas Day, and are completely free to enter and explore. Interpretative guided tours are available Monday to Saturday for a small fee, and are free on Sundays.
[UPDATE] Thanks to everyone who contacted me I know know what this is 
Gunnera manicata, known as Brazilian giant-rhubarb or giant rhubarb, is a species of flowering plant in the family Gunneraceae from the coastal Serra do Mar Mountains of Santa Catarina, Parana and Rio Grande do Sul States, Brazil. In cultivation, the name G. manicata has regularly been wrongly applied to the hybrid with G. tinctoria, G. × cryptica.
Gunnera manicata is a large, clump-forming herbaceous perennial growing to 2.5 m (8 ft) tall by 4 m (13 ft) or more. The leaves of G. manicata grow to an impressive size. Leaves with diameters well in excess of 120 cm (4 ft) are commonplace, with a spread of 3 m × 3 m (10 ft × 10 ft) on a mature plant.The largest on record had leaves up to eleven feet (3.3 meters) in width. The underside of the leaf and the whole stalk have spikes on them. In early summer it bears tiny red-green, dimerous flowers in conical branched panicles, followed by small, spherical fruit. Like most gunneras, it has a symbiotic relationship with certain blue-green algae which provide nitrogen by fixation.
Despite the common name “giant rhubarb”, this plant is not closely related to true rhubarb. It was named after a Norwegian bishop and naturalist Johan Ernst Gunnerus, who also named and published a description about the basking shark.
In 2022, it was shown that plants in cultivation under the name Gunnera manicata in Britain and Ireland, and likely elsewhere, were actually a hybrid, Gunnera × cryptica. It is primarily cultivated for its massive leaves. It grows best in damp conditions such as near garden ponds, but dislikes winter cold and wet.