Subfile 6. Panama, undated

The Erythrina series contains seven subfiles. Subfile 1 includes 153 species files with a corresponding index card file and files on doubtful species and old keys. Subfile 2 concerns African species and symposia papers. Subfile 3 covers correspondence and reports of Dr. Kenneth Rinehart, Dr. David Millington, Dr. R. Hargreaves, and Dr. John Romeo. Subfile 4 concerns Guatemala projects. Subfile 5 is symposia and supplement reprints. Subfile 6 covers correspondence with various scientists, Waimea species, and a geographical list of countries not represented in the seed collection. Subfile 7 is an index card file listing species by region and samples collected for a study done by Karl Folkers et. al. on chemical studies of alkaloids. Krukoff's studies centered on the paralyzing chemicals in the tree's seeds. According to his widow Ruth, "He loved Erythrina. He was obsessed by it. It was his world."