seedless plants and the vascular seedless plants. These plants have had a great impact on all
our lives. Over 300 million years ago, during the Carboniferous period, forests looked very
different than they do today. Seedless plants grew as tall as today’s trees in vast swampy
forests (Figure10.7). The remains of these forests formed the fossil fuel coal that we depend
on today. Although most of these giant seedless plants are now extinct, smaller relatives
still remain.
Figure 10.7: Seedless plants were dominant during the Carboniferous period, as illustrated
by this drawing. ( 30 )
Nonvascular Seedless Plants
Since the nonvascular seedless plants lack vascular tissue, they also do not have true roots,
stems, or leaves. Remember that vascular tissue moves water, food and nutrients throughout
the plant. By definition, roots, stems and leaves must contain vascular tissue. However,
nonvascular plants do often have a “leafy” appearance and can have stem-like and root-like
structures. These plants must also remain very short in stature due to their lack of ability
to conduct nutrients and water up a stem. The appearances of the nonvascular plants
vary, however, and they are classified into three phyla: the mosses, the hornworts, and the
liverworts.