Question

What is "rhytidome"?

• A. Bark
• B. Dead tissue separated by periderm on outside of bark
• C. Dead tissue separated by periderm on inner side
• D. Secondary cortex

Answer 1

The correct option is B Dead tissue separated by periderm on outside of bark

The outer bark on trees, which lies external to the last formed periderm is also called as the rhytidome. Layered outer bark, containing cork and old, dead phloem, is known as rhytidome.

The dead cork cells are lined with suberin, a fatty substance that makes them highly impermeable to gases and water. Gas exchange between the inner tissues of bark-covered roots and stems and their surroundings takes place through spongy areas (lenticels) in the cork.