These members of the Sunflower Family consist of a head of many long-petaled ray flowers, typically yellow, orange or white.
or 
Flowers consist of a central disc of small, short petaled flowers often tightly packed together surrounded by a ring of longer petaled flowers. The longer, outside flowers may be white, yellow, pink, blue, or lavender.
Daisy or sunflower-like flower heads
or 
Button or pincushion-like flower heads: Ray flowers generally not present.
Flower heads are very loosely arranged, with loose clusters of small, short petaled flowers.
Yarrow Achillea millefolium: Flowers white, numerous, in flat-topped clusters. Individual flowers have 4-5 ray flowers with small central disks. The individual flowers are easy to distinguish as they are very loosely packed together. The leaves are almost fern like, and are very dissected (pinnately compound leaf). The plant is covered with short, white cottony hairs. The plant has a strong odor. Plants to 3 feet tall.
Shrub-like Members of the Sunflower Family in the Columbia River Gorge