CH. II] CHARACTERISTICS OF PLANTS 11 



group, which is much older, as shown by fossil remains in 

 the rocks. 



2. THE FERNS AND THEIR KIN, called scientifically PTERI-, 

 &QEHYTES or "Fern plants/' comprise not only the familiar 

 true Ferns, but also the less prominent Horsetails and Club 

 Mosses. They have no flowers, but reproduce by small one- 

 celled spores and a definite though not prominent sexual 

 stage. They live chiefly on land, have green leaves, and 

 make their own food. They are mostly undergrowth plants, 

 though some in the tropics become trees. They have evolved 

 (it is likely but not certain) from the following group, and 

 were formerly more prominent than now, having once formed 

 great forests, the earliest of such vegetation. 



3. THE MOSSES AND THEIR KIN, called scientifically 



or "Moss plants," comprise the true Mosses 



with the Liverworts. They reproduce like the Pteridophytes, 

 by spores and a sexual stage. They have green leaves and 

 make their own food, but they rise little from the ground, 

 on which they grow densely together, thus forming the 

 simplest carpet vegetation of the earth. They are de- 

 scended from the Algae, and were probably the first plants 

 to cover the land. 



4. TjiE MOLDS AND THEIR KIN, called scientifically 

 FUNGI, comprise a great number of small or minute plants 

 most of which are found associated with the disease and 

 decay of plants or of animals, e.g., mushrooms, yeasts, 

 molds, rots, rusts, mildews, and bacteria, popularly known 

 as microbes or germs. They occur in the most diverse situa- 

 tions7T3uT"always' irr contact either with living tissues, upon 

 which they live PARASITICALLY, or else with dead organic 

 substances, upon which they live SAPROPHYTICALLY. They 

 are most diverse in forms, sizes, colors, and other features, 

 in accordance with their particular habits, but never show 

 the green color of the higher plants. They reproduce by 

 minute spores, which are carried everywhere by the winds, 

 thus explaining how those plants can occur in so many 



