212 SPECIAL EXERCISES ON TYPICAL FLOWERS 



181. TOADFLAX OR BUTTER AND EGGS 



Toadflax is a common weed of roadsides and fields. Its 

 bright color and curious two-lipped flowers are always 

 attractive to the student. 



Method (Laboratory). Make a drawing of the entire 

 plant, showing its strict habit of growth, position, and 

 shape of leaves on the stem, and kind of flower cluster 

 (spike). 



Remove a flower and draw it enlarged. Notice the pe- 

 culiar shaped corolla (labiate or two-lipped). Of how many 

 petals is each lip composed ? Compare the upper and under 

 lips as to color, surface, and shape. Take the flower be- 

 tween the fingers and pinch it gently. What happens? 

 Look into the open throat of the corolla and see how many 

 stamens and pistils can be seen. Cut open a corolla, being 

 careful not to injure the essential organs. Draw. How 

 do the stamens compare in length ? Their number ? 



From your knowledge of pollination, how is this plant 

 able to give and receive pollen? Examine the spur as was 

 suggested in the exercise, on the violet. Does it contain 

 nectar? Draw a bud, showing how the petals are folded 

 in the bud. Draw a stamen enlarged. Remove the corolla 

 and draw the essential organs, naming all parts shown. 

 Draw one of the fruits (capsules). Cut an ovary crosswise 

 and draw it, showing the placenta, seeds, ovary walls, par- 

 titions if any, etc. From a ripe or nearly ripe capsule, 

 remove a seed and examine it with a magnifier. What 

 peculiarity have they? 



Method (Field). Study toadflax in the field. What in- 

 sects visit this flower ? How do they enter it ? Are there 

 any special structures which aid a bee to get into the corolla ? 



