SEATTLE — Seattle University plans a service next week for a former educator who disappeared while mushroom hunting near Lake Wenatchee and is feared dead. Searchers were unable to find Hildegard Hendrickson who was last seen June 8, heading out alone. The 79-year-old taught at Seattle University from 1967 to 1996 and headed its department of economics and finance. She also was a mushroom expert with the Puget Sound Mycological Society. The Seattle Times reported that a Mass will be celebrated for Hendrickson at the Seattle University chapel Monday.