found: Work cat.: Von Oettingen, S.L. Small whorled pogonia (Isotria medeoloides) recovery plan, 1992.
found: Hortus 3:p. 607 (Isotria verticillata = Green adderling = Purple five-leaved orchid. Synonym is Pogonia verticillata)
found: Web. 3:entry under whorled pogonia-- "or whorled snakemounth: a No. American green-flowered terrestrial orchid ((Isotria verticillata) with a whorl of five leaves)
found: Britton, N.L. An illustrated flora of the northern United States and Canada, 1970:p. 561 (Isotria verticillata = Whorled pogonia. Synonyms: Arethusa verticillata, Pogonia verticillata, Whorled snake-mouth)