Shanleya’s Quest: A Botany Adventure for Kids Ages 9 to 99 by Thomas J. Elpel (2003)

In a mythical world where time is a liquid that falls as rain upon the land, young Shanleya paddles her canoe out to the tree islands to learn the plant traditions of her people. Each island is home to a separate family of plants and an unforgettable Guardian with lessons to teach about the identification and uses of those plants.