adhesive: firm attachment to a surface by way of molecular forces.
annulus: a specialized ring of thick-walled cells around the sporangium.
auricle: an ear-shaped appendage.
bifurcated: divided into two branches.
bipinnate: pinnate with secondary branches that are also pinnate.
cohesive: referring to the molecular force between particles (e.g., molecules) of a substance that acts to unite them.
distal: situated away from the point of origin or attachment.
epiphyte: a plant that grows on another plant but does not parasitize it.
frond: the leaf of a fern.
gametophyte: the sexual haploid (1n) form of a plant where there is an alternation of generations; the gametophyte produces gametes (eggs and sperm).
indusium (pl. indusia): an epidermal outgrowth that covers the sorus.
lip cells: a specialized patch of cells on the sporangium that split apart to release spores.
petiole: the stalk of a leaf or leaflet.
pinna (pl. pinnae): the leaflet of a pinnate leaf.
pinnate: resembling a feather; having parts arranged on each side of a common axis.
rachis: the axial structure of a pinnate arrangement, like the shaft of a feather.
rhizome: a perennial, prostrate, underground stem, usually rooting at nodes and sending up shoots.
sorus (pl. sori): a cluster of sporangia in ferns.
sporangium (pl. sporangia): the structure in which spores are formed.
spore: a reproductive body (2n) that gives rise, directly or indirectly, to a new organism.
sporophyte: the asexual diploid (2n) form of a plant where there is an alternation of generations; the sporophyte produces spores.
stipe: a supporting stalk; the leaf stalk of a fern.
tensile strength: tensile is the state of being stretched or strained; tensile strength is the greatest longitudinal stress a material can bear without tearing apart.
tripinnate: a bipinnate leaf where the tertiary divisions are also pinnate.
