The time when days start to become noticeably shorter, the nights more crisp, and the colors on the landscape more rich-late August into September-is one of my favorite times of the year. Several species of false-foxgloves blooming on prairies and savannas add charm to the season. Below I briefly profile a few that I have seen thus far this year.
Purple false-foxglove (Agalinis purpurea), an annual, is the most common species in SE Wisconsin. It occurs, sometimes in great abundance, on stream banks, in fens, and in low prairies. It favors the conditions created after fires or in areas that otherwise have sparse vegetation.
Eared false-foxglove (Tomanthera auriculata) was long thought to be extirpated from Wisconsin. Now, two extant populations are known. At this site, which was burned this spring, there may have been a hundred thousand or more plants in a three or four acre area. I missed peak flowering, but there were a few hold-outs. This annual species is partially parasitic (hemiparasitic), and heath aster (Symphyotrichum ericoides) is the favored host.
Large-flowered yellow false-foxglove (Aureolaria grandiflora) occurs in oak savannas. It is hemiparasitic and requires the presence of members of the white oak group such as bur oak (Quercus macrocarpa) and white oak (Quercus alba). These plants were growing in remnant savanna on a small “island” rising nearly 100 feet out of surrounding marsh.
Annual Yellow false-foxglove (Aureolaria pedicularia) is similar to the former species, but it requires members of the red oak group, particularly black oak (Quercus velutina) and northern pin oak (Quercus ellipsoidalis) as hosts. It is often found in sandy oak barrens.
All of the above species are pollinated primarily by bumble bees. I dropped the ball not getting any bees in the photos.