Polygonaceae: Knotweed Family — Chorizanthe (Spineflower)
Flowers in this family do not have separate petals and sepals. Where this is the case, the term “perianth” is used to describe the flower (i.e. the calyx and the corolla together) and “perianth parts” to describe the individual elements, whether or not they are distinguishable. Most of what is seen in the spineflowers are the involucres and involucral membranes. The flowers themselves are 6-lobed, usually but not always a similar color to the involucral membranes.