exogen

Thân thiện

A young student examines an exogen's stem cross-section under a classroom microscope.

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)

Học thuật

Noun

1. flowering plant with two cotyledons; the stem grows by deposit on its outside

Từ đồng nghĩa

• dicot
• dicotyledon
• magnoliopsid