108 Elementary Work in Botany. 



for a time nourish the rapid growth of the tap root, which 

 later gives up its store of food to the stem. 



Examine the flowers. What kind of inflorescence ? Is 

 it bracteate. Are the sepals just alike ? Are they exactly 

 in a whorl ? Remove the sepals and compare with the 

 drawings representing them in Fig. 83. Which sepals have 

 each a stamen opposite to them; that is, exactly between 

 them and the pistil ? Are the spaces between the claws 

 of the petals equal ? Remove the petals. Which 

 stamens are outside or stand lower on the receptacle 

 than the others ? Are the anthers extrorse or introrse ? 

 Can you find the parts represented by two dark spots on 

 the plan of the flower shown in the figure ? What flowers 

 have you examined which have a similar plan ? Do you 

 consider it a sign of close relationship if the flowers of two 

 plants have the same plan ? Which are of the most 

 importance in classifying plants, the characters of the 

 roots, or of the leaves ? 



Hold one of the leaves so that the light shines through 

 it. Compare its veins with those shown in the drawing. 

 Leaves having such veins are said to be netied-veined. All 

 our native trees, except palms and yuccas, and most herbs, 

 have such venation. When the leaves are netted-veined 

 we expect to find the stem with pith surrounded by more 

 or less of woody fiber; the flowers with their parts not 

 all in threes, and seeds containing embryos with two 

 cotyledons. These are characteristics of exogens. 



Make a thin cross-section of the stem. Draw it. If 



