- Name also: Toothed Wintergreen, Serrated Wintergreen, Sidebells Wintergreen, One-sided Wintergreen
- Family: Heather Family – Ericaceae
(formerly Wintergreen Family – Pyrolaceae)
- Growing form: Perennial wintergreen herb. With subterraneous runners.
- Height: 5–20 cm (2–8 in.).
- Flower: Corolla narrowly campanulate (bell-shaped), greenish, 5–6 mm (0.2–0.24 in.) long; petals 5. Calyx 5-lobed. Stamens 10. Pistil a fused carpel, single-styled, (stigma 4–5-lobed), straight, green. Inflorescence with nodding crown, a one-sided raceme.
- Leaves: Alternate, in two whorls at base, stalked, overwintering. Stalk shorter than blade. Blade elliptic, taper-tipped, serrated, leathery.
- Fruit: Roundish, 4–5-lobed, nodding capsule. Stem erect in fruiting stage.
- Habitat: Young and swampy forest heaths, mountain birch woodland.
- Flowering time: June–July.
Nodding wintergreen is a modest plant which has lent substance to the wintergreens’ scientific name Pyrola, ’little pear’. The species’ leaves resemble pear (Pyrus) leaves to the point that nodding wintergreen which is not flowering can be mistaken for a sapling pear or apple tree. Initially all the Wintergreen family species that grow in Finland were grouped into the same genus, but nodding wintergreen and a few other species were later separated into their own small genus. Nodding wintergreen’s genus is monotypic, meaning that it contains just one species, although on the other hand this single member has a lot of variations. The main reasons for moving nodding wintergreen into its own genus are microscopically small, but it can be distinguished from its closest relatives by its nodding, one-sided inflorescence and the leafiness of the lower part of the stem. Over a couple of years the shoot acquires a new leaf whorl, until the plant terminates in its inflorescence. Like many real wintergreens, nodding wintergreen typically grows in broad, quite sparse stands, which it forms vegetatively through its runners. When old runners die and wither, new shots become independent plants.
Wintergreens like the shade and coolness of coniferous forests. They assimilate efficiently even in low temperatures, which makes it easier for them to thrive in the gloom of the forest floor. Many wintergreens have become rarer in recent years due to demands on their habitats – although happily they are not yet endangered. Nodding wintergreen doesn’t avoid people to the same extent as other wintergreens and it hangs on tenaciously in different kinds of clearances, and can even be found in old meadows. It seems to seek out the light because mall stands are often found beside roads and paths. It mainly belongs to southern and central forests in Finland, where it is common, but it also grows in bogs. In the north it is clearly rarer, but it still grows on fell tundra, albeit often without flowering.