INERT MATTER. When found on a seed label this term means the percent by weight of any material other than viable seed.

INFLORESCENCE. The flower cluster of a plant and the way it is arranged.

INFILTRATION RATE. The speed at which water enters the soil surface. Usually measured in inches per hour.

INOCULUM. A pathogen or its part that infects. That portion of the pathogen which is transferred to the plant or plant part for inoculation.

INTEGUMENT. A seed coat.

INTERCALARY MERISTEM. Regions of cell division at the base of leaves and internodes, as distinguished by the apical meristems of stems, buds, and roots.

INTERNODE. The stem region between two nodes.

INVOLUTE. A condition where the leaf blades are rolled inward.

ION. An electrically charged atom, from salts that are dissociated in solution.