A skirt guard [in this case crochet] was necessary for ladies who cycled in long skirts. The guard prevented the skirt flapping into the spokes and causing an accident and preventing mud from splashing up. Modern cycles don't even have a mud guard.
Booktopia has 400 Knitting Stitches, A Complete Dictionary of Essential Stitch Patterns by Potter Craft. Buy a discounted Paperback of 400 Knitting Stitches online from Australia's leading online bookstore.