What is a great uncle?

My Great-Uncle Arthur was a fascinating character, though I only knew him through stories. He was a renowned botanist, not a famous one with books written about him, but respected within his field. He spent most of his life working at a small, almost forgotten botanical garden in the Welsh countryside. He wasn't interested in fame or fortune; his passion was cultivating rare and endangered orchids. He lived a simple life, often found covered in mud and wearing clothes patched with various fabrics. He was fiercely independent and a bit of a recluse, preferring the company of his orchids to people. However, family lore paints him as a kind, if eccentric, man with a surprisingly dry wit. He supposedly once single-handedly saved a local population of a rare Welsh bluebell from developers, using his knowledge of the local council regulations to his advantage. He died peacefully in his sleep surrounded by his beloved orchids at the age of 87, leaving behind a legacy not of publications, but of a flourishing garden and the fond memories of those who knew him.