544 



General Botany- 



striking contrast to the orchids, which represent the most spe- 

 cialized family of the monocotyledons, in which the flowers are 



Fig. 350. Flower clusters of dahlia, sunflower, and thistle, members of the 

 composite family. The small flowers are collected in heads, surrounded by 

 bracts. 



few and the seeds are produced in enormous numbers in each 

 capsule. 



The composites include the various species of chicory, dande- 

 lion, lettuce, ragweed, cocklebur, aster, sunflower, ironweed, 

 goldenrod, fieabane, everlasting, rosinweed, conefiower, Spanish 

 needle, chrysanthemum, and thistle. Many of these plants are 

 weeds, some are cultivated as ornamentals, and a few are of eco- 

 nomic importance as food. 



REFERENCES 



In addition to the well-known manuals : 



Harshberger, J. W. Pastoral and Agricultural Botany. P. Blakiston's Son & Co., 

 Philadelphia ; 1920. 



RoBBiNS, W. W. The Botany of Crop Plants. P. Blakiston's Son & Co., Phila- 

 delphia; 1917- 



Saunders, C. F. Useful Wild Plants of the United States and Canada. Robert M. 

 McBride & Co., New York; 1920. 



Willis, J. C. Manual and Dictionary of the Flowering Plants and Ferns. The 

 Macmillan Company, New York; 1919. 



