exogen
Definition
Noun: 1. A flowering plant with two cotyledons; a dicotyledon: In botany, an exogen is a plant whose stem grows by the deposit of new layers on the outside of the woody tissue beneath the bark. This growth pattern is characteristic of dicotyledonous plants.
Usage
- The term exogen is a technical, scientific term used primarily in botany and plant biology. It is synonymous with "dicot" or "dicotyledon."
- It is used to classify and describe a major group of flowering plants based on their seed structure (having two embryonic leaves or cotyledons) and their stem growth pattern (secondary growth from a vascular cambium, adding layers outward).
Examples
- Noun:
- An oak tree is a classic example of an exogen, displaying clear annual growth rings.
- Botanists historically divided angiosperms into endogens and exogens based on their growth habits.
Advanced Usage
- The term exogen originates from historical botanical classification systems, contrasting with endogen (a plant that grows from the inside, like a monocotyledon). While still accurate, the modern terms "dicotyledon" (dicot) and "monocotyledon" (monocot) are more commonly used in contemporary plant taxonomy.
Variants and Related Words
- Exogenous (adj): Originating from or due to external causes. In botany, it can relate to external growth.
- The plant showed an exogenous response to the applied fertilizer.
- Dicotyledon (n): The modern, more common synonym for exogen.
- Roses, sunflowers, and beans are all dicotyledons.
Synonyms
- Dicotyledon (dicot)
- Broad-leaved plant (in a general, non-technical sense, though not all dicots have broad leaves)
Antonyms
- Endogen (n): A plant whose stem grows by additions to the inside; a monocotyledon.
- Monocotyledon (monocot)
Noun
-
flowering plant with two cotyledons; the stem grows by deposit on its outside
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