Can't really say what the main body of volunteers did as Jim and I got separated early on and spent about two hours wandering Spears south of the picnic grove. It seems we covered the same ground as the others, just at a different time.
It was a good walk; highlights included some way-cool fungi (see below) and a larger patch of native jewelweed than any I've encountered.
Our main target was Japanese hedge parsley, a relatively new invasive (our stewards have been talking about it maybe for a couple years) which is popping up all around the area. While Jim and I didn't encounter much, the main group brought back several bags for disposal.
It's prime time for prairie blazing star - the purple spikes are blooming for your enjoyment in most prairie settings now. Sundown Meadow has an embarrassingly large profusion of the blooms, also seen below.