Lexington Mrs. Clarissa D. (Donham) Morse, of Lexington, formerly of Weston, died Wednesday July 19, 2006 at Brookhaven at Lexington. She was 98. She was the wife of the late Lovett Morse and mother -in - law of the late Richard K. Brown She leaves three daughters, E. Ann Salot and her husband, Dr. William H. of Grosse Pointe Shores, Michigan; Joan M. Rosengard and her husband, Donald L. of Wellesley and Ellen M. Brown of Grafton. She also leaves a sister, Elizabeth Castle of Pebble Beach, California. She is survived by ten grandchildren and twenty-one great-grandchildren. Born in West Medford, she was the daughter of the late Harold G. and Elizabeth (Schneller) Donham. A graduate of Vassar College with a degree in chemistry, she furthered her studies on the graduate level at Harvard University. Mrs. Morse was an active volunteer at the Robert Gould Shaw House in Boston, the former Boston Psychopathic Hospital and the Newton-Wellesley Hospital. She was a long time supporter and patron of the Boston Symphony Orchestra and a former member of the First Parish Church in Weston. Funeral services and burial will be private.