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..
Pyrola uliginosa Torr. Fl. N. Y. 1: 453. pl. 60. 1843.
Pyrola rotundifolia var. uliginosa A. Gray, Man. Ed. 2, 259. 1856.
Scape 6'-15' high, 7-15-flowered. Leaf-blades broadly oval, or orbicular, dull, rather thick, obscurely crenulate, obtuse at both ends, sometimes truncate at the base, equalling or shorter than their petioles; bracts shorter than or equalling the pedicels; flowers purple, 5"-8" broad; calyx-lobes ovate-oblong or ovate-lanceolate, acute or obtuse, one-fourth to one-third the length of the obtuse petals; stamens and style declined-ascending; anther-sacs beaked; style slightly exserted; capsule about 2\" in diameter.
In swamps and bogs, Newfoundland to Alaska, Vermont, central New York, Michigan, in the Rocky Mountains to Colorado, and to California. Similar to the Asiatic P. incarnata Fisch., and perhaps not specifically distinct from it. June-July.
Pyrola asarifolia Michx. Fl. Bor. Am. 1: 251. 1803.
Pyrola rotundifolia var. asarifolia Hook. Fl. Bor Am. 2: 46. 1834.
Similar to the preceding species. Leaf-blades reniform, usually wider than long, coriaceous, shining above, obtuse at the apex, cordate at the base, crenulate, 1'-1 1/2' long, usually shorter than their narrowly margined petioles; flowers racemose, nodding, purple, or rose, 6"-8" broad; calyx-lobes triangular-lanceolate or ovate-lanceolate, acute or acuminate, about one-third the length of the obtuse petals; stamens and style decurved-ascending; anther-sacs slightly beaked; style exserted; capsule about 3" in diameter.
Pyrola oxypetala Austin; A. Gray, Man. Ed. 5. 302. 1867.
Scape slender, 7'-9' high, about 9-flowered. Blades ovate, coriaceous, dull, acute or acutish at the apex, narrowed at the base, obscurely crenulate, 7"-10" long, shorter than their petioles; flowers racemose, ascending, greenish, 4"-5" broad; bracts shorter than their pedicels; calyx-lobes triangular-ovate, acute, about one-third the length of the elliptic-lanceolate acuminate connivent petals; stamens and styles slightly declined; anther-sacs slightly horned.