Late August is the best time of year to observe many species in the Asteraceae, the Aster family, as their flowers bloom and blanket the landscape in yellow and white.
This is specifically true of goldenrods and asters, in the Astereae tribe of the massive Asteraceae family. These species often appear similar but are easier to distinguish when they bloom. You can observe the whole spectrum of diversity within this tribe on a short loop through the Pond Meadow at Gilsland Farm Audubon Center in Falmouth.
Most asters in North America are in the genus Symphyotrichum, often referred to as the American asters (to differentiate from the mostly Eurasian species in the genus Aster). The most common species in the Pond Meadow is New York Aster, Symphyotrichum novi-belgii, which also has the most typical aster flower head, known as capitula in this family due to their unique structure. New York Aster has many quarter-sized capitula that range from nearly white to purple with yellow centers. The two colors differentiate the central, yellow “disk” flowers from the outer, white-to-purple “ray” flowers, which look like petals. This species is just starting to bloom now, so you’ll have to look closely for it!
The most common aster blooming now in the Pond Meadow is Tall White-aster or Flat-topped Aster, Doellingeria umbellata, which is—you guessed it!—both tall and flat-topped. This species actually looks a lot like most of the goldenrod species, with a single, tall stem that only divides at the very top. The white-and-yellow capitula are arranged in a single, flat layer, unlike most Symphyotrichum asters that have more-branched stems and capitula at multiple levels.
Telling the goldenrods apart is a bit more complicated: there are three species of tall meadow goldenrods, with few lower (basal) leaves and nodding, yellow inflorescences (clusters, or flowers growing from one common stem). Smooth Goldenrod, Solidago gigantea, has smooth stems and leaves, Common Wrinkle-leaf Goldenrod, S. rugosa, has very hairy stems and “wrinkly”, hairy leaves. Canada Goldenrod, S. canadensis, is in-between, with rough stems and “downy” leaves (smooth with slightly hairy veins on the underside). This is all complicated by the fact that these characteristics can vary, but the important thing is that all three of these native species fill similar niches in this meadow habitat.
Like the asters, there is another genus of goldenrods represented in the Pond Meadow: Common Grass-leaved-goldenrod or Flat-top Goldenrod, Euthamia graminifolia. This species of goldenrod actually looks a bit more like a Symphyotrichum aster before it flowers, with a similarly-branched stem that is then covered in smaller clusters of yellow capitula. It often grows in wetter soils, like Tall-white Aster, and the two can be seen growing together especially along the Pond Meadow Trail closest to the Pond itself.
Walking the Pond Meadow this time of year is a testament to the utility of this important group of plants. You will likely see Monarch butterflies feeding on the flowers, late-nesting American Goldfinches and Cedar Waxwings foraging for seeds and insects in the foliage, and perhaps a young Woodchuck or Wild Turkey taking cover in the shade beneath. Amidst all this activity, see if you can tell these different species of asters and goldenrods apart!
