How many letters does the top answer for “collected into a rounded head of flowers.” have?

The most common answer is agglomerate (11 letters).

Crossword clue: collected into a rounded head of flowers.

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

agglomerate 11 letters web-def

form into one cluster

agglomerated 12 letters web-def

clustered together but not coherent