August

Yellow false foxglove, Aureolaria grandiflora, is one of my favorite flowering plants. In late summer the showy yellow blossoms bloom throughout the open woodlands of the East Savanna. A hemiparasite on the roots of white oaks it produces its own chlorophyll but obtains water and nutrients from oak roots. Bumblebees are particularly attracted to the profuse tubular yellow blossoms which come into bloom in late July and August. They crawl into the tubular shaped corolla to gleen nectar. According to Wilhelm and Rericha’s Flora of the Chicago Region Bombus affinis, B. griseocollis, B. impatiens and B. vagans visit these large yellow flowers. (Only B. griseocollis and B. impatiens have been observed at Timberhill.)

Bumblebee gleaning nectar in Yellow false foxglove

Silver spotted skippers are the most abundant skipper species at
Timberhill. That’s not surprising since the larvae feed on legumes such as false indigo, bush clover and tick-trefoils, all particularly abundant here. The caterpillars live in shelters constructed by folding over a carefully cut leaf section tied down with white silk. In the photo below you can see the caterpillar on the upper leaf and a folded over shelter on the lower leaf.

When the cup plant, Silphium perfoliatum, came into bloom in August I was surprised to see butterflies nectaring on it. It is not considered a popular nectar source for butterflies. But I observed tiger, black and giant swallowtails and American ladies on the blossoms.