238 



PRINCIPLES OF PLANT-TERATOLOGY. 



these distinct from sy nan thy as clue to the imperfect 

 partition of a single structure. It is often difficult, 

 when confronted with compound flowers, to know 

 whether one is dealing with partition or synanthy. 

 Each case must be decided on its own merits ; and 

 synanthy may only be definitely determined where it 

 can be shown that an actual displacement of flowers 

 on the axis has taken place, or where an apparently 

 compound flower is known to be replaced in a normal 

 inflorescence of the same or an allied species by two 

 or more free, separately-organized flowers. 



R. R. Grates describes interesting cases of synanthy 

 in the evening-primrose (CEnothera)* ; he states that 

 every polymerous flower has two bracts at its base 

 instead of one ; the bracts may be independent or 

 more or less coalesced at the base. The ovary and 

 hypanthium were more or less flattened. " An exami- 

 nation of the stems which bore these polymerous 

 flowers disclosed the fact that they exhibited irregu- 



* Some of Dr. Gates' observations on CEnothera are here appended 

 (K = calyx, C = corolla, S = stamens, N = stigma-lobes). 



K 7 C 7 S 14 N U 

 K 6 C 6 S 12 N 8 . 

 K 6 C 6 S 12 N S 

 K 4 C 4 S 8 N 4 . 

 K 4 C 4 S 8 N 5 . 



K 3 C 3 S 6 N 6 

 K 3 C 3 S 6 N 4 

 K 3 C 3 S 8 N 5 

 K fi C fl S 1Q No 



0. multijlara 



{Race No. 25 from 

 j near Liverpool 



[ 0. biennis x Lamarck- 

 „ [iana 



0. grandijlora from 

 Alabama. 



Race 54 x 40. 

 0. biennis, Chelsea 



Phvsic Garden. 



9. K 5 C 5 S?N? . 



10. K 5 C 5 S 8 N 8 . 



11. K 5 C 5 S 8 N 8 . 



12. K 5 C 5 S 8 N 8 . 



13. K 5 C 5 S 8 N 7 . 



14. K 5 C 5 S S N 5 . 



15. K 5 C 5 S 8 N 5 . 



16. K 5 C 5 S 8 N 5 . 



17. K 5 C 5 S 8 N 5 . 



18. K 5 C 5 S 8 N 5 . 



19. K 5 fC 4 S 9 N 4 



f Two sepals of normal width, three narrower, occupying" about the width 

 of the other two. 



Two bracts at base of flower. 



Two bracts partly coalesced. 



Two bracts at base. 



Two perfect 4-merous flowers with 

 their hypanthia in contact through- 

 out their length and partly fused. 

 Ovaries in contact, and partly 

 fused. Two bracts 



One bract. 



One bract. 



One bract. 



Hypanthium and ovary flattened. 



One bract. 

 One bract. 



Only one bract at base of each flower 

 in this race. In one case the bract 

 had two tips, as though resulting 

 from the incomplete coalescence of 

 two bracts. 



