Ryskamp, Charles, ed. Nineteenth Report to the Fellows of the Pierpont Morgan Library, 1978-1980. New York : Pierpont Morgan Library, 1981, p. 178-188, 210.
Part of 108 drawings of ferns, flowers, and fungi by Ehret and others; seventy-three by Ehret (1978.8:1-73); fourteen by James Bolton (1978.9:1-14); ten possibly by William Lewin (1978.10:1-10); two by R. Alves Rebello (1978.11:1-2); one by Lady Frances Howard (1978.12); one by Ann Lee (1978.13); seven by anonymous draftsmen (1978.14:1-7).
Part of a group originally assembled by Georg Dionysius Ehret's patron, Margaret Cavendish Harley Bentinck (1715-1785), Duchess of Portland, wife of William, 2nd Duke of Portland.