Head stone inscription from Steenbergen Cemetery:
Mrs. Luanna Richner 1/9/1959

Carl Frederick's death Certificate lists her as Louanna Martin Richner. I have no idea if her maiden name was Martin or Holmes

There is an alternate and more contemporary description of the headstone listing at Steenbergen :
D-6-1
Holmes, Dolly L.
1930-1989
D-6-2
Richner, Louanna Holmes
1869-1959
D-6-3
Holmes, John R.-At Rest
Feb. 14, 1865-May 17, 1900

The Holmes surname explains the E. I. or J. E. Holmes informant on Charles's death certificate and the photos from the 1972 Latham History Book-p.102