Scentless chamomile (mayweed, scentless mayweed, daisy)
Matricaria perforata

Distinguished by its white daisy-like flowers and its finely divided fern-like leaves. The flowers are solitary at the ends of smooth, erect or semi-erect branches and measure 2 to 3 cm in diameter. Plants range from 15 cm to over 1 m in height and tend to be bushy when not subjected to competition. The seeds are dark brown, 2 mm long, rectangular and have prominent wing-like ribs that are paler than the kernel. The root system tends to be large and fibrous but does not run or creep.
A similar plant, often mistaken for scentless chamomile, is ox-eye daisy. These plants can be differentiated by their leaves and growth habit. Scentless chamomile has finely divided leaves while those of ox-eye daisy are entire and notched but not divided. Scentless chamomile has several to many flowers on each flowering stem while ox-eye daisy has a solitary flower on each flowering stem.