- An American surname.
- 1905, Edgar Harvey Defebaugh, Barrel and Box and Packages, volume 10, page 50:
- Mr. Guirl is a native of Indiana, and his partner, Mr. H. A. Daggett, who was born in Maine, joined him at Clay City about six years ago.
- 1969, Cactus and Succulent Journal of Great Britain
- The rosette for the best succulent went to Mrs. H. Guirl for her Gibbaeum heathii, a splendid plant with some 20 heads.