This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Parnassia Kotzebuei C. & S. Linnaea 1: 549. 1826.
Scape slender, 3'-7' high, leafless, or sometimes with a single sessile oval leaf near the base. Basal leaves short-petioled, membranous, ovate or oval, narrowed or sometimes cordate at the base, 3"-12" long; flower 4"-5" broad, calyx-lobes oblong, equalling or slightly shorter than the elliptic white 3-5-veined sessile petals; staminodia 3-5 at the base of each petal, rather slender, united below.
Quebec to Labrador, Alaska, Alberta and Wyoming. Summer.
Parnassia palustris L. Sp. Pl. 273. 1753.
Scape slender, 3'-12' high, bearing a clasping ovate leaf below the middle, or rarely leafless. Basal leaves slender-peti-oled, ovate, obtuse at the apex, usually cordate at the base, 9"-18" long; flower 6"-12" broad; calyx 1/4-1/2 shorter than the elliptic few-veined sessile petals; staminodia 9-15 at the base of each petal, slender, united below.
In wet places, Newfoundland, Quebec and Labrador to the Canadian Rocky Mountains and Alaska, south to Minnesota, Michigan, North Dakota, and in the Rocky Mountains to Wyoming. Also in Europe and Asia. July-Sept.
Parnassia parviflora DC. Prodr. 1: 320. 1824.
Scape 4'-12' high, very slender, usually bearing a clasping oval leaf at about the middle. Basal leaves petioled, oval or ovate, narrowed at the base, not cordate, 6"-12" long; flower 4"-8" broad; sepals equalling or somewhat shorter than the elliptic sessile petals; staminodia 5-7 at the base of each petal, slender, united below.
In wet places, Newfoundland and Labrador to Alaska, Quebec, Michigan, Wisconsin, and in the Rocky Mountains to Colorado and Utah. July-Sept.
Parnassia asarifolia Vent. Jard. Malm. pl. 39. 1803.
Scape 10'-20' high, bearing a clasping nearly orbicular leaf at about the middle. Basal leaves long-petioled, orbicular or much broader than long, rounded, broadly kidney-shaped at the base, often 2'-3' wide; flower about 1' broad; calyx-lobes oval, much shorter than the strongly veined elliptic petals, which are rather abruptly narrowed into a claw; staminodia 3 in each set, slender, about the length of the stamens, or somewhat shorter, distinct to the base.
In wet places, mountains of Virginia, West Virginia, North Carolina and South Carolina. July-Sept.