I f the flowers have stalks, it is a raceme, the most common f orm of inflorescence. If the raceme is irregularly or alternately branched, it is a panicle. If it is oppositely and regularly branched, it is a cyme. But if the flower stalks ar i se from different positions on the axis and are different lengths but arrive at the same level and appear flat-topped, it is a corymb. A head generally is composed of two types of flowers the outside ring of usually colorful ligules or ray flowers and the inner tubular or disk flowers.
Most flowers consist of four series of parts.
The outside series or ring usually is green, but in lilies, this series may be colored, is called the calyx, and is comprised of sepals. Within the calyx is the corolla, comprised of the highly colorful and showy petals. The calyx and corolla together are called the perianth. The next series just inside the petals are stamens. Each stamen consists of a relatively slender stalk, called the filament, tipped with a pollen-bearing anther.