FERTILIZATION OF SPEING FLOWERS ON THE YOBKSHIRE COAST. 143 



Table VI. for Tmsilago, Bellis, and Salix). Of these dominant 

 species, which, as shown in Table IV., were alike much frequented 

 by short-tongued flies, three belong to Class B', and Salix to Class A. 



Table V. — Competition among the Dominant Flowers for the 



AVAILABLE InSECTS. 



Consideration of some Special Cases. 



Ranunculus Ficaria, which so extremely rarely sets seed, is an 

 enigma. This failure in seed-production cannot be due to want of 

 fertilization, for the flowers are visited by a considerable variety of 

 insects, though not very freely. The mid-tongued bees are fewer in 

 number with us than in Germany or Belgium, and in consequence 

 we find fewer species on the flowers of this plant. The following is 

 a comparison of the species visiting. In this and the following 

 cases the statistics for Low Germany are drawn from the works of 

 H. Miiller,* those for Belgium from that of MacLeod. t 



Comparing '95 and '96 {see Table VI.), we note that in the 

 second year insects of mid- tongue length (Andrena and Syrphidfe) 

 appear to visit less seldom, while the more inefficient fertilizing 

 agent Scatophaga takes their place. 



Cochlearia officinalis. — It is now well established that the 

 biological features of the flower may differ in difl'erent parts of the 

 plant's distribution-area. This species offers an instance. Kn'uth 

 failed to perceive nectaries in the flowers of North Friesian plants, J 



* Fertilization of Floivers, and ' Weitere Beobachtungen,' i., ii., & iii. in 

 Verhandl. d. Nat. Vcrein d, Preuss. llheinlande, xxxv. (1878), xxxvi. (1879), and 

 xxxix. (1882). 



t ' Over de Bevruchting der Bloemen en het Kempisch gedeelte van Vlaan- 

 deren.' Bot. Jaarboek, v. 15(i (1893), and vi. 119 (1894). 



t Bltimen und Iim'kten atif den nordfriesi^chcn Inseln. Kiel & Leipzig, 1894, 

 p. 29. 



