5. Pyrola grandiflora Radius, Pyrola & Chimaphila. 27, plate 3, fig. 2. 1821.
Large-flower or arctic wintergreen, pyrole grandes fleurs Large-flower or arctic wintergreen, pyrole grandes fleurs
Pyrola grandiflora var. canadensis (Andres) A. E. Porsild; P. grandiflora var. gormanii (Rydberg) A. E. Porsild
Plants rhizomatous, 0.5-1.9(-2.5) dm. Leaves: petiole 10-65(-80) mm, channeled adaxially, glabrous; blade not or, sometimes, maculate, dull and light green to purplish abaxially, shiny and dark green, sometimes with white tissue bordering larger veins adaxially, ovate to elliptic or round to subreniform, 9-33(-45) n 10-50 mm, coriaceous, base truncate to rounded or cordate, margins subentire to crenate or crenate-serrulate, apex rounded to acute. Inflorescences 1 per stem, 4-12-flowered; peduncular bracts absent or 1-3, ovate-lanceolate to ovate, 6-12 × (2-)3-5 mm, chartaceous or membranous, margins entire; inflorescence bracts ovate-lanceolate to ovate, longer than subtended pedicels, 4.5-10 × 1.8-3.4 mm, chartaceous. Pedicels 3-8 mm. Flowers: calyx lobes appressed or spreading in fruit, green, pinkish, or reddish with margins hyaline to white or pinkish, oblong-ovate to lanceolate, (2.2-)2.8-6 × (0.9-)1.2-2 mm, margins entire or erose-denticulate, apices obtuse to rounded; petals white, often suffused with pink, obovate to round, 6-10(-11) × 4.2-6 mm, margins entire or erose-denticulate, especially distally; stamens 4-7.5 mm; filament base 0.2-0.3 mm wide; anthers 1.6-3 mm, apiculations absent or less than 0.1 mm, thecae creamy yellow to golden yellow, tubules yellow to yellowish brown, 0.1-0.3 mm, scarcely narrowed above thecae, lateral walls touching for most of their lengths, pores 0.1-0.2 × 0.1-0.2 mm; ovary smooth; style scarcely exserted, 4.5-8 mm; stigma 0.7-1.1 mm wide, lobes erect. Capsules depressed-globose, 2.9-4 × 3.8-6 mm. 2n = 46, 69.
Flowering Apr-Jun. Arctic and alpine tundra, heathlands, coniferous forests, boreal forests and woodlands; 10-2000 m; Greenland; Alta., B.C., Man., Nfld. and Labr. (Labr.), N.W.T., Nunavut, Ont., Que., Sask., Yukon; Alaska; Eurasia.
A. E. Porsild (1939) recognized three varieties in Pyrola grandiflora (var. canadensis, var. gormanii, and var. grandiflora) differing subtly in leaf and floral morphology, floral fragrance, and habitat. Variation among these taxa appears to be essentially continuous. E. Haber (1972) referred them to synonymy [under P. rotundifolia subsp. grandiflora (Radius) Andres] without discussion. Hybrids between P. grandiflora and P. minor have been reported from western Greenland; they were discussed by T. W. Böcher (1961).