in Botany, a sheath; a species of calyx which bursts lengthwise, and protrudes a stalk supporting one or more flowers, which commonly have no perianthium or flower-cup.

SPATHACEÆ (from spatha, "a sheath"), the name of the ninth order in Linnaeus's Fragments of a Natural Method, consisting of plants whose flowers are protruded from a spatha or sheath. See Botany Index.