I discovered the native perennial Whorled Loosestrife, Lysimachia quadrifolia, during yesterday's late afternoon walk.
I found this interesting piece taken from a book written quite some time ago by Mrs. Dana:
"This slender pretty plant grows along the roadsides and attracts one's notice in June by its regular whorls of leaves and flowers. Linnaeus says that this genus is named after Lysimachus, King of Sicily. Loosestrife is the English for Lysimachus but whether the ancient superstition that the placing of these flowers upon the yokes of oxen rendered the beasts gentle and submissive arose from the peace suggestive title or from other causes I cannot discover."
Here's a view across the lake from the above photos a short time later.
Dana, Mrs. William Starr. How To Know The Wildflowers. New York, 1920. Google Book Search. Web. 13 Jun 2009.