1. A type of vascular cylinder in plant stems characterized by a ring of vascular bundles surrounding a central pith, found in dicots and some other plants.
Usage: botany; technical term

Examples

• The eusteles of dicotyledonous plants typically show a clear ring of vascular bundles.
• In plant anatomy, the eusteles represents an intermediate stage of vascular organization.
• The stem's eusteles arrangement allows for secondary growth in woody plants.
• Botanists identify eusteles by observing the circular pattern of vascular tissue in cross-section.