Paet I 



STRUCTURE AND PHYSIOLOGY OF 

 SEED PLANTS 



INTEODUCTORY STUDY OF A SEED PLANT 

 AND ITS OEGANS 



1. The common dwarf nasturtium (Tropaeolum).^ 



A. The plant body. Take a plant -which has been carefully dug 

 up and note the division of the plant body into three sets 

 of parts or organs, roots, stems, and leaves, which constitute 

 its main bulk. 



Make a reduced drawing to show the general form and 

 proportions of the entire plant. 



B. Roots. Note the general form and arrangement of the roots 

 and the differences between roots and stem in size, shape, 

 color, and texture. 



C. Stem. Make a reduced drawing of a portion of the stem, 

 with parts of two or three leafstalks, showing how they are 

 attached to it. Does the stem branch ? Is it solid or hollow ? 



D. Leaves. Make a reduced drawing of one of the largest 

 leaves, including the leafstalk, and life-size drawings of two 

 or three of the youngest leaves near the tip of the stem. 

 Note the mode of attachment of the leafstalk to the expanded 

 portion, blade, of the leaf, the course of the veins through 

 the blade, and the differences between the upper and lower 

 surfaces of the latter. 



1 Any plant witli well-developed roots, stems, and leaves, and simple, conspicu- 

 ous flowers, will answer for this study. Good types available in autumn are the 

 garden balsam, the wild yellow oxalis (0. cymosa), the petunia, any of the 

 Gerardias, etc. 



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