So, Morgan and I sat down in front of my perfume cabinet with my scent dictionary, and we found her a smell :) Let me tell you the story...
Moonflowers are delicate white flowers belonging to the morning glory family, which have traditionally represented innocence and naivety. Very Morgan.
They are often found growing in swampland and near large bodies of water; rivers, lakes, streams-- being a water elemental, this suits her just dandy.
Moonflowers are named so because they flower at night, releasing their sweet fragrance. Weavers too tend to flower at night, releasing their powers into the sleeping minds of dreamers.
Furthermore, in medieval times, flowers were used to send secret messages between people. Morning glory and moonflowers were sent to convey the message 'I love you in vain', which fits in very nicely with how this came to be her scent! Miles and Morgan have been best friends for over fifteen years, and he's been hopelessly in love with her for most of that. One year, for her birthday he gifted her a bottle of moonflower perfume. Morgan didn't seem to realize that perfume is a rather intimate gift to give someone-- and she certainly missed the message about him loving her in vain!
One last snippet of trivia: When ingested, the seed of the moonflower, as well as various other parts of the plant, is a powerful hallucinogenic.