
“In the cover design by Margaret Armstrong the books and authors are represented by the following symbolic flowers: Bible—grapes; Psalms—wheat; Dickens—English holly; Thackeray—English rose; George Eliot—ivy; Keats bleeding-heart; Wordsworth—daffodil; Browning—pomegranate; Izaak Walto—strawberry; Johnson—oak; Stevenson—Scottish bluebell.”
from Campanionable Books (1922) by Henry van Dyke
Just quick note, this book, recommended by Per in comments below, is a real gem. I must learn more about it. In particular, who is this Solomon Singlewitz and “The Life of Adam”?