28.1
How Did the Land Plants Arise? 611
There are ten major groups of land
plants 611
The land plants arose from a green
algal clade 612
28.2
How Did Plants Colonize and Thrive
on Land? 613
Adaptations to life on land distinguish
land plants from green algae 613
The nonvascular plants usually live
where water is available 614
Life cycles of land plants feature
alternation of generations 614
The sporophytes of nonvascular plants
are dependent on gametophytes 616
28.3 What
Features Distinguish the Vascular
Plants? 616
Vascular tissues transport water and
dissolved materials 617
Vascular plants have been evolving
for almost half a billion years 618
The earliest vascular plants lacked
roots and leaves 619
The vascular plants branched out 619
Roots may have evolved from branches
619
Pteridophytes and seed plants have
true leaves 620
Heterospory appeared among the vascular
plants 621
28.4
What Are the Major Clades of Seedless
Plants? 622
Liverworts may be the most ancient
surviving plant clade 622
Hornworts have stomata, distinctive
chloroplasts, and sporophytes without
stalks 623
Water and sugar transport mechanisms
emerged in the mosses 623
Some vascular plants have vascular
tissue but not seeds 624
The club mosses are sister to the
other vascular plants 624
Horsetails, whisk ferns, and ferns
constitute a clade 625
