We recently cataloged this set of dishes that has long been displayed in the Boon House Dining Room (M3 73-25-56).
Trolling the internet for information on the unique caduceus hallmark found on the bottom of these pieces (see photos above), we came across similar marks on pieces by Bishop & Stonier, an English ceramics producer. They, and their successor organization, appear to have been in business using this mark and the trade name BISTO from 1891-1939. This set which includes dinner, luncheon and dessert plates, saucers, gravy boat, sugar bowl and large vegetable dishes. They were originally donated by Mrs. Albert Powers to help furnish the Boone house when it was opened in the mid 1970s.