Glossary: I

imbricate: Overlapping, as shingles on a roof; arrangement of bud scales with the outer/lower ones overlying and partially concealing the inner/upper ones.
imparipinnate: A compound leaf with pairs of leaflets and a single terminal leaflet (compare with paripinnate).
incised: Cut deeply into visible lobes (but not quite teeth).
indehiscent: Not separating or splitting open at maturity.
indeterminate: A structure that develops from the base and continues to elongate or expand throughout the growing season.
indument: Outgrowths of the epidermis that are only 1 cell wide (i.e., hairs); a collective term for all of the hairs on a plant or on a plant organ.
indurate: Hard, firm.
indusium: A specialzed flap of tissue that covers and protects the sorus in ferns (plural: indusia).
inferior ovary: The ovule-bearing organ of a flower that has the other floral parts (calyx, corolla, etc.) attached to its summit.
inflorescence: Flower array; arrangement of flowers on a stem.
infructescence: Arrangement of fruits on a stem.
internode: The portion of the stem between two nodes, i.e. where leaves or branches join it.
introrse: Curved inward.
invasive: A species noted as rapidly spreading or a noxious weed in the indicated New England state.
invest: To enclose or envelope.
involucral bract: One of the many leaf-like bracts that surround the base of the capitulum in Asteraceae; synonym "phyllary".
involucre: A grouping of many involucral bracts, which are modified leaflets that grow at the base of an inflorescence or flower, as in the "cup" of an acorn in members of the oak family (Fagaceae).
involute: Rolled inward/upward toward the adaxial surface.