26 



PRELIMINARY STUDIES. 



FIG. 4. Transverse section of stem of a 

 Burdock. (X 35.) 



24. The fruit and seed. The entire ovary, together 

 with such parts of the flower as become united with it, 



develops into the fruit. 

 Each ovule develops into 

 a seed, which is the end 

 for which the plant ex- 

 ists. For the study of 

 the different kinds of 

 fruits and seeds, consult 

 Gray's " School and Field 

 Botany," pp. 117-128. 



25. The stem. Make 

 an examination of the 

 general construction of 

 the stems of the Elder, 

 Willow, Maple, Castor- 

 oil Plant, House Geranium, Burdock, etc. With a sharp 

 knife cut across the stems near their tips. Moisten the cut 

 ends, and examine their 

 structure under a mag- 

 nifying glass. At the 

 center is pith ; in some 

 stems of rapid growth 

 the pith has parted and 

 the stem is hollow. Out- 

 side of the pith is a ring 

 of wood, and outside of 

 the wood is the bark. 



Cut through stems 

 of trees where they are 

 of considerable size. 

 Use a magnifier, and 

 observe several rings 

 of wood in place of the single ring in the young shoot. 

 In general one ring of wood is formed each year. 



FIG. 5. Part of transverse section of pres- 

 ent year's growth of stem of Basswood. 

 (X 35.) 



