decusar

A highly technical term from heraldry and botany meaning to arrange in the shape of an X — decussate, in English. In heraldry it describes a saltire-like crossing; in botany it describes leaves or branches growing in opposite pairs at right angles to the pairs above and below them. It has essentially no everyday use outside these specialized fields.

• El botánico describió cómo se decusan las ramas de esta especie. — The botanist described how the branches of this species cross in an X shape.
• En heráldica, dos espadas pueden decusarse para formar un aspa. — In heraldry, two swords can be crossed to form a saltire.
• El diagrama muestra cómo se decusan los filamentos. — The diagram shows how the filaments cross each other.

This word is confined to specialist heraldry and botany texts — there's no meaningful everyday mistake to flag beyond recognizing it isn't a verb a learner will need in conversation.