piceous \PIS-ee-uhs, adjective:

1. Inflammable; combustible.
2. Of, pertaining to, or resembling pitch.
3. Zoology. Black or nearly black as pitch.

In the silent and piceous hour just before dawn, they advanced at a slow trot, fanning out through the slave quarters and into the yard that divided the gin house, the mill, and the buildings where Canning and I slept unaware.
— Geraldine Brooks, March

Dark pink for the brick buildings, dark green for the doorjambs and the benches, dark iron for the hinges, dark stone for Nathaniel’s Tomb; darkness in the piceous roots of trees that broke through the earth like bones through skin.
— Roger Rosenblatt, Beet

Piceous stems from the Latin word piceus meaning “made of pitch.”