Viola selkirkii (Selkirk's Violet)
These were almost unseen in the early spring debris of a little watercourse. Viola selkirkii is a rare plant, on the USFS list of "sensitive" plant species. Scott Smith of Denver identified these violets after conferring with Tass Kelso, an expert on violets.
The bulb-like spur on the back of each flower is diagnostic, as are the glassy hairs on the upper leaf surface, and the deep sinus at the base of the leaves.