Cataphyll

In plant morphology, a cataphyll (sometimes also called a cataphyllum, or cataphyll leaf) is a reduced, small leaf. Many plants have both "true leaves" (euphylls) which perform the majority of photosynthesis, and cataphylls that are modified to perform other specialized functions. Cataphylls include bracts, bracteoles, and bud scales, as well as any small leaves that resemble scales, which are known as scale leaves. Some cataphylls have a primary function other than photosynthesis. The functions of cataphylls such as bud scales may be short-lived and they are often shed after the need for them is past.

Etymology

From the Greek Ancient Greek: κατά, down, Ancient Greek: φύλλον, leaf.

Forms of cataphylls

Some kinds of cataphylls perform a transient function, after which they die and may be shed. Those that are shed early are said to be caducous, but that term can apply to any organ that is shed early, not only leaves; for example, many Geraniums have caducous stamens. The sepals of Papaver species are shed during the very opening of the petals, and as such they are a dramatic example of caducous leaves. Many other forms of cataphylls, such as some spines, are persistent, but cannot perform their major function until they die, whether they physically get shed or not. Examples of various kinds of cataphylls include bud-scales, bulb-scales, corm-scales, rhizome-scales, cotyledons, scaly bracts, spines. Each of these occurs in various forms and contexts; for example, bud-scales occur on various kinds of leaf or branch buds as well as on flower buds.