hypogeal. Said of seeds (as garden pea) in which the cotyledons remain under ground in germination. See [epigeal].

imperfect flowers lack either stamens or pistils.

incomplete flowers lack one of the parts or series, as the calyx, corolla, stamens, or pistil.

indeterminate. See [centripetal].

indusium. The scale or lid covering a sorus, in ferns and allied plants.

inflorescence. Properly, the mode of flowering (page 160), but sometimes used in the sense of a flower-cluster.

involucre. A set or whorl of leaves or bracts beneath a flower or a cluster of flowers; sometimes looks like an outer or extra calyx.

irregular flowers have some members of one or more of the series unlike their fellows.

key fruit. See [samara].

labiate. Lipped; that is, divided into parts, as the lips of a mouth. Said usually of corollas that are lobed into two parts.