spathe

Spathe is a botanical term for a large, often colorful bract that surrounds or subtends the inflorescence in many plants of the family Araceae. The true flowers are borne on the spadix, a dense spike that rises within the spathe.

Typically the spathe consists of a tubular portion, the spathe tube, and a limb or hood that may envelop the spadix. In many Araceae species the spathe is showy and leaf-like, functioning to attract pollinators, while the flowers themselves are tiny and inconspicuous. In some genera the spathe forms a chamber or hood that can guide or trap insects briefly to facilitate pollination.

Pollination in Araceae often involves a combination of scent, light, and sometimes heat production. Thermogenesis, the deliberate generation of heat, occurs in some species such as the titan arum and related plants, helping volatilize odors and attract insects. The spathe can thus play a central role in the plant’s reproductive strategy by enhancing pollinator visitation and guidance toward the spadix.

Not all spathes are ornamental: in genera such as Zantedeschia (calla lilies) and Anthurium, the spathe is a prominent, decorative feature, while in Philodendron and some Arum species it may be more modest or persistent.

Etymology: the term spathe derives from Latin spatha, from Greek spathē, meaning “blade” or “sword,” referring to the leafy, blade-like bract surrounding the inflorescence. A spathe should not be confused with the spadix, the spike that carries the flowers.