This framed artwork is a "Hattie leaf" painting, a traditional and delicate souvenir unique to Pitcairn Island in the South Pacific by descendents of HMS Bounty.
These pieces are created by hand-painting designs directly onto the transparent "skeleton" of a dried leaf.
The craft is named after Hattie André, a missionary who arrived on Pitcairn in 1893. To help the islanders generate income, she taught them weaving and this specific method of painting on leaves from the Bauhinia monandra tree, which grows abundantly on the island. These became popular items for islanders to sell to passing ships, a tradition that continues today. 
Creating a Hattie leaf is a labor-intensive, "smelly" process that requires significant patience, Green leaves are soaked in water for four to six weeks until the green membranes rot away, leaving only the delicate vein structure. The leaf skeletons are carefully washed with soap, dried, and then ironed flat to create a smooth canvas , oil-based paints thinned with kerosene are brushed onto the leaf.