In
plant morphology, a
cataphyll (sometimes also called a
cataphyllum or
cataphyll leaf[Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928]) is a reduced, small
leaf.
Many plants have both "true leaves" (
euphylls), which perform most of the
photosynthesis, and cataphylls, which are modified to perform other functions.
Cataphylls include , and bud scales, as well as any small leaves that resemble scales, known as .
Etymology
Cataphyll comes from the
Ancient Greek ("kata"), meaning "down", and ("phyllon"), meaning "leaf".
Forms
In some cases, cataphylls perform a function, after which they die and may shed. Those that shed early are said to be caducous. The
of
Papaver species are shed during the very opening of the
Petal and are a dramatic example of caducous leaves.
Cataphylls can have many other forms. Some, such as spines, Corm, and Bud, may be persistent but may not perform their major function until they die, whether or not they are physically shed. Examples of various kinds of living cataphylls include Bulb, Rhizome, , and scaly .
Protective masses of dead leaves encircle the stems of some species of Arecaceae or , but those are not usually regarded as cataphylls because their primary function while alive is photosynthesis.
Cotyledons as cataphylls
are widely regarded as a class of cataphyll,
though many kinds of cotyledons function as living tissue and remain alive until, at least, the end of their function, at which time they wither and may drop off. They begin as leaf
rudiments. Many kinds accumulate nutrient materials for storage, starting to give up their stored material as the plant germinates. Some, such as the
of many
,
Pinophyta, and
Cucurbitaceae, develop chlorophyll and perform the first
photosynthesis for the germinating plant.
Corm scales
Like bulb-scales,
corm scales are largely the basal parts of the photosynthetic leaves that show up above ground. Some species of cormous plants, such as some
Lapeirousia, also produce cataphylls that act solely as tunic leaves for the corm.
Unlike bulb-scales, however, the corm tunic has no significant storage function; that task is left to the
parenchyma of the cortex of the corm.
See also
