ABSTRACT
Esau, K. (1977) Anatomy of Seed Plants. J. Wiley and Sons, New York. Hopkins, W.G. (1995) Introduction to Plant Physiology, 2nd Edn. J. Wiley and Sons,
New York. Mauseth, J.D. (1991) Botany: an Introduction to Plant Biology, 2nd Edn. Saunders
College Publishing, Philadelphia. Raven, P.H., Evert, R.F. and Eichorn, S.E (1998) Biology of Plants, 6th Edn. W.H.