PROBLEM 2. The Kinds of Fhmts of the Earth 91 



Class i. Liverworts (Hepaticae): Sonic liave a sonicwivat branched, ribbon- 

 like structure flat on the ground, with simple rootlike parts. Others have 

 stems and rootlike and leaflike parts. 



Class 2. Mosses {Musci): Erect. More complex in structure with stems, leaf- 

 like, and rootlike parts. 

 PHYLUM III. Pteridophytes {Pteridophyta): Plants without flowers and seeds. 



Green. True leaves, roots, and stems with conducting tissue much like that 



in higher plants. 



Class i. Ferns (Filicinae): In temperate zones, mostly small with horizontal 

 stems. Spores borne on leaves or modified leaves. 



Class 2. Horsetails (Eqiiisethiae) : Few species. Jointed stems with leaves 

 reduced to scales. Spores in conelike structures. Stems harsh to touch. 



Class 3. Club Mosses (Lycopodinae): Few species. Creeping herbs with 

 erect stems bearing conelike structures with spores. 

 PHYLUM IV. Spermatophvtes {Speriiiatophyta) : Producing flowers and seeds. 



Practicalh" all are green. Vary in size. Complex structure. 

 SUBPHYLUM I. Gymnosperms {Gyi}mosperi)iae): Woody plants with naked 



seeds born on surface of cone scales. Mostly needle or scalelike evergreen 



leaves. Includes the conifers, ginkgos and cycads. 

 SUBPHYLUM II. Angiosperms {Angiospermae) : Seeds develop enclosed in a 



fruit. 



Class i. Monocotyledons: Usually parallel veined leaves. Flower parts in 

 three's. Single cotyledon in seed. 



Class 2. Dicotyledons: Netted veined leaves. Flower parts mostly in two's, 

 four's, or five's. Two cotyledons. 



Questions 



1. Why is it incorrect to use the words plant and flower as though they 

 meant the same thing? Into what tw^o large groups can all plants be 

 divided? In which group are trees and grasses placed? 



2. What name is given to the division of flowerless plants that includes 

 the simplest plants? What are the characteristics of the plants in this 

 division? What name is given to the simplest plants that are green? 

 What do you call those without green color? 



3. Describe a simple water-dwelling alga and two land-dwelling forms. 

 Do most algae live on land or in the water? 



4. Are mushrooms algae or fungi? Give some interesting facts about 

 mushrooms. 



5. Describe the common breadmold. What is mildew? 



6. What is a lichen? 



7. Tell about the yeast plant: its size, how it looks, how it lives, of what 

 importance it is to us. Define fermentation. 



8. What is your idea of the size of an ordinary bacterium? What might 

 you see if you examined bacteria under the microscope? What is 

 their importance to us? 



9. Which common plants can be classified as Bryophytes? How^ do these 

 plants differ from the Thallophvtes? How is Sphagnum moss used? 



10. In general, where do ferns grow and how do they look? What was 

 true of these forms in ages past? 



