Root Structure of True Ferns

About Ferns

• Ferns developed more than 300 million years ago and there are more than 12,000 species today. They are characterized by leaves called fronds that unfold as spirals that gradually straighten out. Like mosses, they have two separate life stages, the sporophyte and the gametophyte. The sporophyte, the plant we usually think of as a fern, bears a multitude of spores that drop to the ground and grow into a quite different type of plant. This small, flat, heart-shaped gametophyte has both male and female organs. The fertilization of the eggs results in a new sporophyte, a new fern.

The Gametophyte

• Though the gametophyte is short-lived and without vascular tissue, it has root-like rhizoids. These look like fine hairs and anchor the gametophyte to the ground, to moist rocks or to bark.

Roots and the Vascular System

• The true roots, stems and leaves of the sporophyte have a system of tubes called xylem that allows water and nutrients absorbed by the roots to move upward to the fronds. The carbohydrates and proteins produced by photosynthesis can also travel downward to nourish the roots through tissue called phloem. These two types of tissues form the woody part of both ferns and flowering plants.

Types of Fern Roots

• Roots may form at many places along the stem or the rhizome. In tree ferns, they develop at the base of the fronds and grow downward, strengthening the trunk. Some ferns that grow on trees have roots that form a tangled mat to both support the fern and gather moisture. Some ferns have roots that are unbranched, some are forked and others highly branched and developed into a complex system. Some have only roots that have been reduced to fine hairs.