Question

the plants are leathery or _______, dry and tough, and though none are recorded as poisonous, they are too tough to be edible. source: students handbook of mushrooms of america, edible and poisonous annular coriaceous bituminous supple

Explanation:

"Leathery" implies a tough, leather - like texture. "Coriaceous" means leathery or tough - textured, which is a synonym for the description in the sentence. "Annular" refers to ring - shaped, "bituminous" relates to substances like tar, and "supple" means flexible and not tough.

Answer:

B. coriaceous