APPENDIX II 167 



CHAPTER XX 



IMPERFECT, INCOMPLETE, AND UNSYMMETRICAL FLOWERS 



IMPERFECT FLOWERS: 



Read Kerner and Oliver, Volume II, Part i, pp. 291-299. 

 Gray, Text-book, pp. 193 ( 353) and 218 ( 405). 

 Allen, The Story of the Plants, pp. 105 (bottom line)-lO9. 

 Gaye, The Great World's Farm, pp. 208-212. 



I. 6. In this case it is intended to call attention to the 

 more complete crossing in dioecious plants than must neces- 

 sarily take place in monoecious plants. Read, also, Kerner 

 and Oliver, Vol. II, Part i, pp. 300 (section at bottom of the 

 page), 301; and Gray, Text-book, pp. 215 (note under 

 Kerner's " Flowers and their Unbidden Guests"), 216, for 

 the terms Autogamy, Allogamy, Geitonogamy, and Xenogamy. 



II. The perianth, i.e. the floral envelopes (calyx and 

 corolla), serves two separate kinds of functions. First, it 

 protects the maturing essential organs until they are in a 

 condition to perform their functions. Second, it serves, 

 in insect-pollinated flowers, to attract insects both by its 

 color, and by the nectar which it secretes. It is by no 

 means easy to determine in most cases why one or both 

 circles of the perianth are absent. 



Read Gray, Text-book, pp. 187-195. 



III. IV. Irregtilarity is generally explainable after more 

 or less careful study upon the basis of adaptation to insect- 

 pollination. The papilionaceous flower in its various forms, 

 and the flowers of the Larkspur, Monkshood, Pansy, etc., 

 are excellent examples and worthy of detailed study. 



