Nantucket is fortunate to have several species of native wintergreens that retain their foliage through the winter. They are actually easiest to learn to identify during the colder months when most other plants have dropped their leaves and it is easier to see through the understory. Wintergreens are tough woody species in the blueberry family, Ericaceae, and most are considered “sub-shrubs,” with short upright central stems and leathery leaves that grow off of that stem. One of the wintergreens, creeping snowberry (Gaultheria hispidula), is more of a mat forming vine, however. And the shinleafs (Pyrola spp.) lack a central stalk and have only a basal rosette of leathery evergreen leaves. There are many additional species in the Ericaceae found on Nantucket, but the others drop their leaves in fall, or even more peculiarly, lack green leaves entirely, as in Ghost pipes (Monotropa uniflora) and pinesap (Monotropa hypopitys). (These two non-photosynthetic plants were once placed in their own family, Monotropaceae, but have since been included within Ericaceae. More about them in a future blog article!)
Wintergreen (Gaultheria procumbens) is the most common and well-known wintergreen species on island. It grows only a few inches tall and spreads to form colonies with egg shaped leaves on upright stems, bearing bright scarlet berries in fall and through the winter. Because it thrives on sandy acidic soil with a layer of duff and leaf litter, and does best in partial shade, wintergreen makes the most of Nantucket’s forests, heathland, scrub oak shrubland, and even sandplain grassland habitats. The leaves are a hunter green color much of the year; in the winter leaf color dulls to a deep maroon on many plants. As temperatures warm in spring, the previous years’ leaves green up, and new tender leaves are produced at the top of the plant. Wintergreen’s leaves give this plant another of its common names: teaberry. They are filled with methyl salicylate oils which are strongly wintergreen scented and also found in the stems and twigs of black birch. Wintergreen leaves of any stage may be used to make a spicy tea, but the young tender leaves may also be nibbled fresh, before they become too tough.
The unmistakable wintergreen scent and the star shaped indented pattern on the underside of the scarlet berries (a blossom scar that remains after the flowers are pollinated and begin to swell into berries) are characteristics that make it easy to learn to identify this common species. The berries are pure white inside and have a bright red outer skin, and often last into the winter. A great place to learn this species is along the trails in the Serengeti, accessed from Milestone Road at Mile Marker #5 (overlooking the Milestone Cranberry Bog) or, closer to Town, from the new trailhead on Milestone Road that takes you to Altar Rock (just before mile marker #4 on Milestone Road, a little under 3 miles from Town).
Spotted (or striped) wintergreen (Chimaphila maculata) is a less-common species of wintergreen here on Nantucket, where it specializes in pitch pine forests and scrub oak shrublands, inhabiting the thick pine needle or leaf litter. Spotted wintergreen’s leaves are elongated and pointed, with more obvious teeth than wintergreen leaves, and there is an unusual, variegated pattern on the leaves typically including a central lighter colored stripe and some combination of forest green, pale green or cream, and cranberry.
Because of the dramatically striped leaves some people prefer to call this species striped wintergreen. This striking plant can be identified by its distinctive leaves at any time of year, although it’s most obvious in the winter when it stands out against rusty pine needles or a bed of leaf litter. The boldly striped leaves are obvious and present year-round, unlike the spots indicated by both the common and scientific name–the species epithet “maculata,” also means spotted. The spots giving the plant its name are small brown speckles on the flower petals that are easily missed (and only present when flowers are open). So, if you happen to spot a patch in winter or fall, return in early to mid-July to enjoy the lovely nodding cream-to-pink colored blossoms, which have a tendency to become hidden in the lush growth of summer groundcover and shrubs. Spotted wintergreen anthers are shaped like tiny pairs of pantaloons with ruffled ankles, a tubular shape that facilitates “buzz pollination” by native bumblebees, and it is well worth a close look at these interesting flowers, very different in appearance from those of blueberry, huckleberry, and cranberry.
Pipsissewa (Chimaphila umbellata), also sometimes known as noble prince’s pine, in spite of a lack of resemblance to pine trees. Pipsissewa is more uncommon on Nantucket, but often found in habitat similar to its relatives, spotted wintergreen and the shinleaf. It seems more apt to grow in scrub oak alone, so you might expect it to be more common and widespread. The long narrow toothed leaves of pipsissewa are an olive drab to medium green color, lacking a central stripe. Pipsissewa and spotted wintergreen have very similar nodding white to pink flowers that ripen into woody capsules that may be seen in fall and winter, helping with identification. Saul’s Hills in the Middle Moors is a good place to look for pipsissewa.
Creeping snowberry (Gaultheria hispidula) is a vining, mat forming evergreen with rusty-hairy stems and small egg-shaped, toothed evergreen leaves. Like wintergreen, it produces fleshy wintergreen-flavored and scented fruit, but in the case of snowberry the fruit are elongated and pure white, giving the plant its common name. While early botanists have recorded this species in bogs on Nantucket, it has not been seen in recent years and is likely quite uncommon. It shares similar habitat with our native cranberry and is present in all of the New England states, often found in inaccessible bog habitats where it may easily go unnoticed. Records for Nantucket were in bogs on the eastern half of the island and this species could be relocated with more searching in our continuing work to update the Nantucket Flora.
American shinleaf (Pyrola americana) and green flowered shinleaf (Pyrola chlorantha) are the final species pair to round out our Nantucket complement of wintergreens. American shinleaf is the most abundant and widespread on Nantucket and can be found in the leaf litter of mixed deciduous forest but does best in pine and scrub oak. The shinleafs have only basal leaves and no central upright leafy stalk. Look for round to kidney shaped leaves in olive green that barely peek out of the leaf litter. You may also see a dead brown or blackened flower stalk with seed capsules, as the shinleafs do not have fleshy berries. Separating American shinleaf (white flowers) from green-flowered shinleaf is easier when plants are blooming, but shaded plants often do not flower, and can also be hard to find when all of the understory shrubs are in leaf. The length of the leaf stalk (petiole) relative to the length of the leaves must be used to distinguish the two shinleaf species in the dormant season, with the green-flowered shinleaf having leaves that are shorter than the petiole, and the American shinleaf having leaves longer or the same length as the petiole. Green-flowered shinleaf was last collected in 1933 on Nantucket. This is one of those little mysteries remaining in our ongoing work to update the Nantucket Flora. Unfortunately, the best documented area for this plant on Nantucket was near the old fairgrounds, presumably along Fairgrounds Road, an area that is highly developed today. However, as this species is easily confused with American shinleaf, there’s a good chance that it is still present on island in another pine woodlands, hiding in plain sight, so we have been keeping an eye out on our winter walks for any unusual looking shinleaf. The Stump Pond loop trail at Windswept Bog, and trails in the Saul’s Hills part of the Middle Moors are good places to look for shinleaf.