Frond may refer to the leaf structures of palms, cycads, and ferns. In the case of palms and cycads, the word simply refers to leaves that bear no reproductive structures. In the case of ferns, however, the fronds bear the reproductive structures and so are more critically important in the life cycles of the plants.
A fern frond consists of the stipe, or stem below the leaf tissue, the rachis, or stem within the leaf tissue, the laminar (or leaf) tissue, the sori, which bear the spore, and may as well bear hairs or scales, and, in some species, bulblets for vegetative reproduction or glands. Each frond arises from the rhizome or rootstock, which in most species is concealed in the ground or creeping along the ground surface (or branch or rock surface). Fern fronds may vary from simple, untoothed to extremely lacily cut. Each main division of a fern frond, arising from the rachis, is called a pinna if it is stalked. If the leaf tissue is continuous with the rachis, then it is termed a lobe. Many ferns are divided two or more times, and the level of division of the fronds is termed pinnate, or twice-pinnate, or the like. In the case that the pinna is divided into lobes, it is termed pinnatifid. A few ferns with divided fronds do not follow the pinnate division rule, but are palmate or bifurcate.
