THE WATER DEPENDENCE OF MOSSES AND FERNS
1. Why are both mosses and ferns confined to environments where water is abundant
during at least some time of the year?
Mosses and ferns both require water at some point in their life cycles because
both need a watery medium for their flagellated sperms to swim through to
reach their eggs.
2. Describe three characteristics of ferns which make them better suited to a dry habitat
than moss.

Ferns have vascular tissue which can move water from the ground up; from
the rhizomes up to the leaves.

As well, the leaves are coated with a waxy cuticle that helps to limit
desiccation.

Gases can pass into and out of the leaves via openings (stomata) of adjustable
size.
3. Why are ferns able to grow taller than most mosses? What benefits are there, if any,
in being a taller plant?
The vascular tissue of ferns (the xylem in particular) is quite strong, so it lends
support to the plant. Therefore it can grow tall without collapsing. Advantages
of being tall include better access to light and an improved ability to disperse
spores far and wide.
(© 2004. C.K. Robinson, Summerland Community Learning Centre, School District No. 67)