PLANTS IN RELATION TO SOIL, LIGHT, AIR 65 



The exercise does not prove conclusively that plants decom- 

 pose carbon dioxide. The preceding exercise shows that better, 

 but the fact is the only one which explains well the conditix)ns 

 found in a well-balanced aquarium. 



II. Types of Roots. — Study the roots of several different plants 

 from gardens, fields or waste places. The fleshy roots of beets or 

 parsnips may be compared with the long tap-root of clover or alfalfa. 

 Compare these with finely divided fibrous roots of such plants as 

 yarrow, timothy or raspberry. Compare the roots of annual weeds 

 with perennial weeds. Fleabane and ragweed are examples of annuals 

 which have a rather straight tap-root with a number of side roots. 

 The tap-root is hard but not fleshy. Toad flax, oxeye daisy, and 

 dandelion are examples of perennials. Roots of perennials are never 

 as simple as those of annuals. Provision is made for the storage 

 of plant-food in fleshy roots or underground stems. Often buds are 

 formed underground for the growth of plants in following years. 

 See if these can be found. 



If the young gardener will learn by careful observation 

 to note the differences between roots of annuals and perennials, 

 it will aid him in combating weeds of various kinds and in 

 the care of perennial garden plants during the dormant season. 

 Perennial borders must be cared for in fall and early spring, 

 and the gardener should know the different forms of root 

 systems to avoid destroying the valuable plants. 



