PROBLEM 2. The Kinds of Plants of the Earth 



Flowerless Plants 



73 



PHYLUM - THALLOPHYTES 



The simplest plants. The first division, 

 or phylum, of the plant kingdom con- 

 tains plants which differ widely among 

 themselves in appearance and in size. 

 Som.e are single celled and microscopic; 

 others grow to an enormous size. All 

 are alike in that they do not have true 

 roots or stems or leaves and that they 

 never produce flowers or seeds. Some 

 contain the green coloring matter so 

 characteristic of plants. They are called 

 Algae (aPjee). Those that lack the green 

 coloring matter are called Fungi (fun'- 

 jeye). Of the algae some look bright 

 green; in other algae the green coloring 

 matter is more or less hidden by other 

 colors so that these algae may look bluish 

 green or even brown or red. 



The smaller algae. Have you ever seen 

 a green scum on the water of a slowly 



moving stream or small pond? If you 

 lift the scum on a stick you discover that 

 it is a bright green mass of long tangled 

 threads. Each thread consists of a number 

 of cells all alike. If you examine these 

 threads with a microscope, it is likely 

 that you will see a beautiful plant called 

 Spirogyra. Each cell contains one or 

 more green spirals. The plant has neither 

 root nor stem nor leaf. See Fig. 97. It 

 is just a living green thread which grows 

 in the sunny water and may at some 

 time become food for a water animal. 

 With a microscope you can do Exer- 

 cise I. 



In the plant kingdom as in the animal 

 kingdom, the simplest organisms are 

 usually water dwellers. Some of these 

 simple plants have one or several long 

 whiplike projections by means of which 

 they swim. Yes, many species of simple 

 plants move about. Others, such as the 



PTERIDOPHYTES 



Christmas fern 



Naked seeds 



SPERMATOPHYTES 

 Covered seedst* 



Pine tree with cones 



ooming geranium 



are flowerless plants? How many other examples of plants hi each gronp do yoii know? 



