It appears somewhat to look like a, Silene sp. Found near a well established wetland in Coquitlam. About 16 inches tall, leaves about 2 inches max.length, and 1 inch width. Flower is about 1 inch across.
Silene dioica is a close match. Apparently there is also a hyrid between Silene dioica and Silene latifolia var. alba that has been collected in "the lower Fraser Valley and N to Prince George" (from the Illustrated Flora of BC). The book, however, doesn't go into the characteristics of the presumably intermediate hybrid.