Historical Rules · 10 August 2018
Rule 205.3c
Official source text from the 10 August 2018 Rules release
If a card with multiple card types has one or more subtypes, each subtype is correlated to its appropriate card type. Example: Dryad Arbor’s type line says “Land Creature — Forest Dryad.” Forest is a land type, and Dryad is a creature type.