Jack certainly will be missed. Here's a record of his contributions to the database:
10,693 images
173 Plant Combinations
1,800 comments
26,807 plants
15,969 data proposals
43,257 miscellaneous proposals
Always a courteous and kind gentleman, he provided thorough and helpful responses to questions and was generous with his advice on plants in the gardening forums and his recommendations of good books in the Sandbox.