The New Student's Reference Work/Vernation

Verna′tion, the arrangement of leaves in the bud, sometimes called præfoliation. Numerous names have been applied to various forms of vernation. Among the principal ones are imbricate, in which the edge of a leaf overlaps its neighbor; valvate, in which neighboring edges touch, but there is no overlapping; conduplicate, in which the leaves are folded lengthwise; convolute, in which the leaf is rolled from one margin; circinate (characteristic of ferns), in which the leaf is rolled from the apex downward.