Chart Pteris Rhizome
The structure of Pteris rhizome is unmistakably and invariably dorsiventral. In shape the apical cell of the rhizome is a modified form of the dolabrate type. The apical arrangement is considered to be adaptive to the subterranean habit. The endodermis and pericycle have a common origin and both layers are stelar. The protophloem sieve tubes and the phloem parenchyma are derived from a common mother cell, which in turn has a common origin with the mother cell of the endodermis and the pericycle.