Acrogens

Acrogens, or Summit-growers, a name applied to the higher cryptogamic plants, viz. mosses, ferns, horse-tails, and lycopods, in which there are a distinct stem and leaves, the former increasing most notably in length by growth at its apex. The vascular bundles are in a ring, and like the indefinite ones of Monocotyledons, closed, so that the stem increases little in diameter, whilst its apical growth results mainly from the repeated division of one large apical cell.