How many letters does the top answer for “large headed; -- applied to animals, and to plants when they have large flower heads.” have?

The most common answer is megacephalic (12 letters).

Crossword clue: large headed; -- applied to animals, and to plants when they have large flower heads.

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

megacephalic 12 letters web-def

Large headed; -- applied to animals, and to plants when they have large flower heads.

megacephalous 13 letters web-def

Large headed; -- applied to animals, and to plants when they have large flower heads.