Which garment materials are obligated in tzitzit by Torah law, and which only by rabbinic decree?

Synopsis

The Mechaber rules that only wool and linen garments are Torah-obligated in tzitzit; all other materials (silk, cotton, camel hair, etc.) carry only a rabbinic obligation. The Rema (following Tosafot, Rosh, and Mordechai) rules that all garment materials are Torah-obligated.

Early Acharonim
Late Acharonim
Lenient
Strict
Lesser cited
Major authority

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