Pseudanthium

The real flowers (the florets) are generally small and often greatly reduced, but the pseudanthium itself can sometimes be quite large (as in the heads of some varieties of sunflower).

The disk flowers in the center of the pseudanthium are actinomorphic and the corolla is fused into a tube.

[4][5] The individual flowers of a pseudanthium in the family Asteraceae (or Compositae) are commonly called florets.

[8] The collection of independent organs into a complex structure is called synorganization.

and Google Scholar does not link to any significant usage of the term in a botanical sense.[when?]

What appear to be "petals" of an individual flower, are actually each individual complete ray flowers , and at the center is a dense pack of individual tiny disc flowers . Because the collection has the overall appearance of a single flower, the collection of flowers in the head of this sunflower is called a pseudanthium or a composite.
Peace Lily ( Spathiphyllum cochlearispathum ) pseudanthium
compressed pseudanthia of Lepironia articulata
Euphorbia caput-medusae 01
Actinodium cunninghamii pseudanthia