Terälehti

Terälehti, in Finnish botany, refers to the petal of a flower—the individual segment that forms the corolla. The singular is terälehti; the plural terälehdet. They are modified leaves that surround the reproductive organs, often colored and scented to attract pollinators and guide them to nectar. Petals arise from the floral meristem as part of the perianth, together with the sepals that form the outer whorl. Petal morphology varies widely: shape (lanceolate, obovate, spatulate), size, texture, and color; some petals are tubular or fused into a corolla tube, others are separate. Flowers may be actinomorphic (radially symmetric) or zygomorphic (bilaterally symmetric), a feature often determined by petal arrangement. Petals can display nectar guides—patterns visible in ultraviolet light to pollinators.

Functionally, petals primarily attract pollinators and provide a landing platform; in some plants petals also protect the reproductive organs or help direct pollinators to the nectar. After fertilization, petals may wither and fall. In horticulture, cultivated varieties are selected for showy color, shape, and fragrance. Taxonomically, petal morphology is a key character for identifying species and understanding relationships within plant families. The term terälehti is used primarily in Finnish descriptions, while in English it corresponds to the concept of the petal.