Cataphyll

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
The stems of Athrotaxis are covered with small flat pointed leaves called "scale leaves" or "cataphylls".

In plant morphology, a cataphyll (sometimes also called a cataphyllum,[1] [2]or cataphyll leaf[3]) is a reduced, small leaf.[4][5] Many plants have both "true leaves" (euphylls) which perform most of the photosynthesis, as well as cataphylls that are modified to perform other specialized functions.[6]

Cataphylls include bracts, bracteoles, and bud scales, as well as any small leaves that resemble scales, known as scale leaves[2].[4][5] The functions of cataphylls, such as bud scales, may be short-lived, and they are often shed after their function is fulfilled.

Etymology[edit]

Leaf bud of American Sweet gum (Liquidambar styraciflua); the cataphylls covering the bud show a little chlorophyll, but they will be shed instead of growing into photosynthetic leaves.

From the Greek Ancient Greek: κατά, down, Ancient Greek: φύλλον, leaf.[7]

Forms of cataphylls[edit]

In some cases, cataphylls perform a transient function, after which they die and maybe shed. Those that are shed early are said to be caducous, a term that can apply to any organ that is shed early. For example, many Geraniums have caducous stamens. The sepals of Papaver species are shed during the very opening of the petals, and are a dramatic example of caducous leaves.

Cataphylls can have many other forms. Some, such as spines, corm-scales and bud-scales may be persistent but may not perform their major function until they die, whether they are physically shed or not. Examples of various kinds of living cataphylls include bulb-scales, rhizome-scales, cotyledons, scaly bracts.[3] Several of these types occur in various forms and contexts. For example, bud-scales occur on various kinds of leaf or branch buds as well as on flower buds.

Protective masses of dead leaves encircle the stems of some species of palm trees or aloes, but those are not usually regarded as cataphylls because their primary function while alive is photosynthesis, as is usual for true leaves.

Acer pseudoplatanus seedling showing cotyledons that supplied the first photosynthetic function for the growing plant. They will soon drop off after the young leaves grow large enough to take over.

Cotyledons as cataphylls[edit]

Cotyledons are widely regarded as a class of cataphyll,[8] though many kinds of cotyledon function as living tissue and remain alive until the end of their function at least, at which time they wither and may drop off. They begin as leaf rudiments and many kinds accumulate nutrient materials for storage, starting to give up their stored material as the plant begins to germinate. Some, such as the cotyledons of many legumes, conifers, and cucurbits, even develop chlorophyll and perform the first photosynthesis for the germinating plant.

Opuntia compressa, showing a so-called spiny cactus. Each areole contains one or more fixed, large spines as well as a sheaf[disambiguation needed] of glochidia. The spines are examples of cataphylls.[citation needed]

Corm scales[edit]

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 leaves that solely act as tunic leaves for the corm.[9] 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.

  • Crocosmia corm with tunic stripped partly off to show its constitution of the basal parts of leaves arising from nodes on the corm. Such leaves, especially early leaves that never performed much photosynthesis, amount to true cataphylls

  • Corm of Crocosmia, split to show tunic and leaves, as well as a new corm growing from a bud on the cortex of the old corm

See also[edit]

References[edit]

  1. ^ Stearn, W.T. (1992), Botanical Latin: History, grammar, syntax, terminology and vocabulary (4th ed.), David and Charles, ISBN 0-7153-0052-0
  2. ^ a b "Definition of CATAPHYLL". www.merriam-webster.com. Retrieved 2021-10-22.
  3. ^ a b Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928
  4. ^ a b Hickey, M.; King, C. (2001), The Cambridge Illustrated Glossary of Botanical Terms, Cambridge University Press
  5. ^ a b Beentje, H.; Williamson, J. (2010), The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms, Royal Botanic Gardens, Kew: Kew Publishing
  6. ^ Bell, A.D. (1997), Plant form: an illustrated guide to flowering plant morphology, Oxford, U.K.: Oxford University Press
  7. ^ Chisholm, Hugh, ed. (1911). "Cataphyll" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
  8. ^ "What Are Cotyledons, Monocots, and Dicots?". The Spruce. Retrieved 2021-10-22.
  9. ^ Goldblatt, Peter; Manning, John (2008). The Iris Family. Portland: Timber Press. ISBN 978-0-88192-897-6.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Cataphyll&oldid=1055998807"