51. 



Suggestions for the Teacher 



The most important point in connection with the study of 

 plants is to train the powers of observation. The child should 

 learn to discriminate between plants. While important to know 

 the name of a plant, it is far better to be able to tell what the 

 differences are. For instance, we have about 1100 different kinds 

 of flowering plants in the state of Iowa. They differ from each 

 other by one or more characters. The student should learn the 

 most important differences. To illustrate, we have in Iowa, two 

 kinds of morning glory, one the common bindweed or wild 

 morning glory, native to Iowa, with flowers from one to two 

 inches long, leaves large halberd, or arrow shaped, and running 

 rootstocks often called "roots" but these so-called roots have 

 small scales. The European bindweed has much smaller flowers, 

 less than one inch long, leaves small ovate and arrow shaped, 

 and running roots, no scales on these. 



Many people do not know that we have two kinds of dandelion 

 in the state. The common one (Taxaxacum officinale,) olive green 

 seeds and coarsely divided leaves, and the red-seeded one (Tar- 

 axacum erythrospermum) with red or dark brown seed and 

 deeply divided leaves. 



There are eight thistles in the state, all of these are easily 

 distinguished by a very simple key which I will insert here for 

 convenience. The characters are all very obvious. 



A. Perennial. Plants living year after year. 



1. Heads large, numerous. 



a. Leaves woolly both sides Woolly Thistle (C. can- 



escens, N. W. la.) 

 a. Leaves hairy on lower surface Field Thistle (C. 



discolor, la. general. 



2. Heads small. Leaves slightly woolly underneath 



Canada Thistle (C. arvense, la. general.) 



3. Heads large, usually 1, blooms early Prairie Thistle 



(C. Hillii, la. general.) 



B. Biennial. Plants form flowers the second season and then 

 die. 



1. Heads with numerous sharp spines. Leaves very spiny 



