My weekly visits to the bog continue to be worthwhile. During my first July visit, a new (to me) pink-flowered plant was blooming along sections of the boardwalk. Rose Pogonia (Pogonia ophioglossoides), whose identity I later determined, grows throughout New England in bogs and other wet habitats. The plant's stem bears a single leaf, along with a small leaf-like bract located just below the solitary flower. Apparently, stalks can be topped by up to four flowers, but of the hundred or so plants I checked, only one had more than one flower (two in that case).
I identified this bog orchid using Newcomb's Wildflower Guide (Flower type: Irregular Flowers; Plant type: Wildflower with Alternate Leaves; Leaf type: Leaves Entire), and double checked my conclusion with Go Botany's simple online key to 25 New England Orchids. (To view the following images in full-size, click here.)
Note: The final photo contains a skipper butterfly who escaped my notice at the bog.