bigwull, that description of "whitewood" was by Seymour himself written in 1945 at the time of his donation to the society. Since tulip poplar is white in color, i am guessing thats why he called it that. Seymour was born in 1859 in Hartford, was a prominent lawyer and acquired many pieces of early american furniture, all of which he donated to the connecticut historical society at the time of his death in 1945.
I think Seymour was using whitewood as a generic term, in this case, tulip poplar.