It had a good run. The Danforth Foundation gave away more than $1.25 billion over its 84-year existence. But yesterday John and William Danforth announced the philanthropic endeavor will be dissolved later this year. They also announced the final award of the program; a $70 million endowment to the Donald Danforth Plant Science Center in Creve Coeur. The center employs 200 PhD-level scientists that work on basic plant research.