Induplicate (induplicatus). Doubled along the midrib, with the margins turned inwards.

Inferior Ovary (ovarium inferum). An ovary adnate to a concave receptacle or to the tube of the perianth or calyx.

Inflorescence (inflorescentia). The flowering part of a branch and the arrangement of the flowers upon it. The flower-clusters constituting together a compound inflorescence are termed partial inflorescences.

Introrse (introrsus). Turned inwards.

Inverted Ovule (ovulum anatropum). An ovule with the micropyle next to the hilum.

Involucel (involucellum). The involucre of a partial inflorescence.

Involucre (involucrum). A group of bracts surrounding an inflorescence.

Involute (involutus). Rolled inward from the margins towards the midrib.

Irregular Flower (flos irregularis). A flower with unequally shaped or disposed perianth-leaves.

Jointed (articulatus). Divided into portions which subsequently separate; or separating at the point of attachment.