A poetic title for a poetic bit of folklore. In welsh mythology, Olwen is sometimes referred to as 'She of the White track' and closely associated with the Hawthorn tree which is also known as the Whitethorn, and in Pagan terms at least, regarded as feminine. (The masculine equivalent is the Blackthorn or Sloe.)

Anyway, it was believed that at the beginning of time, the Universe was completely empty, and Olwen walked across the heavens, leaving a trail of hawthorn petals in her wake; these became known as the Milky Way.

I just thought it was a nice story! :)