Lewis & Short

sarmentīcĭus or -tĭus, a, um, adj. [sarmentum], of or belonging to twigs, cuttings, or brushwood: cinis, Col. 6, 26, 3.
In plur. subst.: sarmentīcĭi, ōrum, m., the Christians, who were burned with fagots, Tert. Apol. 50.