PT ae ee ae ee ee ee ee 
THE GENERAL CHARACTERISTICS OF PLANTS 13 
minute germs of decay and disease, the slime molds, the yeasts, 
molds which occur on bread, cheese, fleshy drugs, some phar- 
maceutical preparations, etc., the water molds, some of which 
attack the gills of fishes, the mildews, the mushrooms and toad- 
stools, and many forms which cause plant diseases, such as the 
smuts, rusts, chestnut tree blight, ergot of rye, etc. There is 
another subdivision of Thallophytes 
called Licuens which comprises the 
leathery-like growths which occur on 
the bark of trees, on rocks and the 
soil of woodland. They are peculiar 
plants in that each represents a living 
together of an alga and a fungus. 
Next to the Thallophytes in order 
of ascending complexity of structure 
come the Bryopuyta or Bryophytes 
[Gk.bryon, moss; phyton, plant}. ‘This 
division includes the liverworts or 
Hepatic and the mosses or Musct. 
The liverworts are small, leaf-like 
plants which occur on moist earth — 
and in water. Some of them are 
thought to be descendants of forms Fic. 7.—A liverwort (Lanu- 
: laria). Below, portions of the 
which were the first plants to take up i palloid body, showing the lunar- 
a land existence. ‘The mosses in- _ shaped cupules, with brood-buds, 
clude pale green forms of swampy 0F S8emma. Above a single 
ground and bogs called peat mosses, ‘Gager) a ee 
the black mosses of siliceous rock, 
and the bright green or common mosses which so conspicuously 
carpet portions of our forests and rocks. (See Figs. 315 and 318.) 
The next highest division is that known as the PreRIDOPHYTA 
or Pteridophytes [Gk. pieris, fern; phyton, plant] which have as 
their representatives the CLus Mosses, HorseETaits or Scouring 
Rushes and the Ferns. While most of these are low growing 
terrestial plants, a few forms are aquatic in habit and some of the 
tropical ferns assume tree-like forms. (See Figs. 325, 329 and 
330.) 
The Thallophytes, Bryophytes and Pteridophytes are col- 
lectively termed the CryPTOGAMS [Gk. cryptos, hidden; gamos, 
