(from follis, "a bag,") a species of seed-vessel first mentioned by Linnæus in his Delicatissima Planter, generally consisting of one valve, which opens from bottom to top on one side, and has no suture for fastening or attaching the seeds within it.

FOLLICULI are likewise defined by the same author to be small glandular vessels distended with air, which appear on the surface of some plants; as at the foot of water-milfoil, and on the leaves of aldrovanda. In the former the leaves in question are roundish, and furnished with an appearance like two horns; in the latter, pot-shaped, and semicircular.