(d) : Transfusion tissue is a specialized tissue present on either side of midrib in between the palisade and spongy tissues of the leaf of Cycas and also in Pinus leaf at the sides of the sclerenchymtous region. It is made of horizontally arranged tracheids. These supply water and minerals to mesophyll tissue upto margins so that the mesophyll cells can carry out photosynthesis. It is of two types primary transfusion tissue present next to the midrib bundle and secondary transfusion tissue that runs upto margins of the leaf. In Pinus it consists of tracheids and albuminous cells.