饅頭菊 ・ まんじゅぎく ・ manjugiku | 万寿菊
A type of chrysanthemum (kiku) with many small petals and an almost ball like shape. Often stylized as a round shape consisting of multiple rows of overlapping small (round) petals.
Two different ways of writing the name in kanji exist, manju (万寿) referring to it's longevity, or manju (饅頭) referring to the manju-shape of a traditional (ball shaped) Japanese sweet with the same name.
See also Kiku.