20 STUDY OP COMMON PLANTS. 



II. GROWTH OF PLANTS FROM THE SEED. 



MATERIAL REQUIRED. 



Seedlings of the common bean, pea, sunflower, white mustard, flax, 



and hemp, from one to four weeks old.^ 

 Seedlings of Indian corn and wheat of various ages. 

 Pine seedlings from a few weeks to a few months old. 

 Seeds of squash and other cucurbits in early stages of germination. 



I. Take seedlings of different ages of the plants named 

 in the first list above. Wash the roots and let them stand 

 in a dish of water to prevent drying. Compare them and 

 satisfy yourself as to the following points : 



1. Do they all have a taproot? 



2. Do they all have a hypocotyl, i.e. a stem supporting 



the cotyledons? 



3. How do the cotyledons of the different plants differ 

 a. As to form and size? 



h. In function ? Have any of them wholly lost their 

 function as foliage leaves? Are there any 

 apparently transitional forms, as if this function 

 were partially lost ? 



4. How does the pea differ from the sunflower in the 



time of unfolding the proper foliage leaves ? Can 



1 The seeds should be sown at intervals of a few days, some in sand, 

 others in moist (not wet) sawdust, and still others on folds of damp 

 blotting paper under a bell-jar. There should be three or four lots of as 

 many difierent ages. Pine seedUngs, which are rather difficult to raise, 

 may be obtained from nurseries. 



