Anatomy Of Dicotyledonous And Monocotyledonous Plants

When the fibres possess very thick walls and reduced simple pits, they are known as libriform wood fibres because of their similarity to phloem fibres. Libriform wood fibres chiefly occur in woody dicotyledons. There are many transitional forms between the fibres and normal tracheids. These transitional forms are designated as fibre tracheids. A line of demarcation cannot be drawn between tracheids and fiber tracheids.