Eliza Gerrard (née Riley) was a deceased character from Sad Cypress. She passed away 14 years prior to the novel.
She was a maid at Hunterbury for Mrs. Laura Welman, a wealthy widow, before her marriage to Ephraim 'Bob' Gerrard. At some point she was with child without being wed and was abandon by Bob Gerrard. Mrs. Welman took her under her wings and the child ended as stillborn, but later Mrs. Welman was with a child of her own from an affair with Sir Lewis Rycroft. After the death of Sir Lewis, Mrs. Welman took Eliza Riley with her to Scotland, where the baby (Mary) was born. It was decided that Eliza should claim the child as her own, hence protecting Mrs. Welman from a scandal.
Bob Gerrard took contact again with Eliza Riley and they got married. Bob became the lodgekeeper of Hunterbury and agreed to pass the baby, which he thought was Eliza's, as his own. The baby was named Mary Gerrard, Mary after Eliza's sister, who immigrated to New Zealand. Out of sense of duty, Eliza Gerrard wrote the truth about Mary's birth in a letter, which she wanted entrusted to her sister upon her death. After her death Bob Gerrard send the letter, but sadly the letter ended giving Mary Riley inspiration on how to get her hands on Mrs. Welman's fortune, which resulted in the deaths of both Mrs. Welman and Mary Gerrard.