This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
As the genus Sabbatia is called annual or biennial in our text books, I would say that I have specimens of S. lanceolata with the remains of last year's flower growth, this year's flowers, and crowns at the base for next year's flowers ; also, S. chlorides with last year's flower stem and this year's flowers.
I notice, also, that Amphicarpum Purshii is called by Wood perennial, and by Gray, annual or biennial. I have specimens with both kinds of flowers mature, and the seed from which it grew attached, which would point to its annual nature.