Glider, its not a mystery. Just something unfamiliar to you. I am certain they are d. brevifolia, but also look into the ranges of d. capillaris, and see if that is more likely. HOWEVER! D. capillaris has pink flowers, not white. D. intermedia has white flowers, and are completely different looking from what you have. Brevifolia can have white flowers, or pink. D. brevifolia is very small! Less than an inch across, and more commonly, around 1/2 inch.