MOSSES, LIVERWORTS, AND FERNS 281 
Group B. Bryropny res 
Crass I. Hepatic (liverworts). Genus used as illustration — 
Marchantia 
Crass II. Muscr (mosses). Leading genera used as illustrations — 
Atrichum and Sphagnum 
Group C. PrermopuytTes 
Crass I. Fiticrn (the true ferns). Leading genera used as illus 
trations — Pleris (the bracken fern), .fd/antim (the maidenhair 
fern), Onoclea (the sensitive fern, or oak fern) 
Crass II. Equisetin-& (horsetails, or scouring rushes). Genus used 
as illustration — Equisetum (the only living genus of the class) 
Crass HI. Lycoropix x (club mosses or ground pines). Genus used 
as illustration — Lycopodium (one of the three living genera of 
the class) 
PROBLEMS 
1. Of what importance are mosses as soil formers? 
2. What is the significance of the radial arrangement of the leaves 
of the moss plants ? 
3. Why is it important to the plants that the asexual spores of 
mosses, liverworts, and ferns should have wide distribution ? 
4. In what sense is it true that the vascular tissue exemplified in 
ferns means about the same to the plant kingdom as the vertebral 
column (backbone) means to the animal kingdom ? 
5. Why is it that peat-bog inoss is good material for covering the soil 
of potted plants and for packing fragile articles for shipping? 
6. In what ways may ferns be propagated vegetatively? How do 
florists propagate their ferns? 
7. What structures of ferns help to explain the fact that most ferns 
thrive best in damp and shaded regions ? 
8. In museums that you have visited what fossil evidences are there 
that ferns lived during former ages ? 
