264 



BOTANY OF THE LIVING PLANT 



is suggested by a line above or below the latter. Other details 

 arc sometimes introduced into floral formulae, but it is best not 

 to overload them. As examples the following formulae for common 

 flowers may be given : 



Lily, P 3+3 , A 3+3 , G(3). (Compare Fig. 187.) 

 Buttercup, S 5 , P 5 , A 00JG 00 . (Fig. 452, App. A.) 

 Myrrhis, S 5 , P 5 , A 5 , G (2). (Fig. 468, App. A.) 

 Primrose, (S 5 ), (P 5 ), A 0+5 , G (5). (Fig. 470, App. A.) 



[For details which will explain these formulae see Appendix A.] 



Factors leading to Differences of Floral Construction. 



The leading factors upon which the differences of floral construction 

 chiefly depend will now be stated and discussed. They are these : 

 (i) Differences in the arrangement of parts on the receptacle, 

 (ii) Meristic differences, 

 (iii) Fusion of parts. 

 (iv) Pleiomery. 

 (v) Meiomery. 



(vi) Various development of the floral receptacle, 

 (vii) Differences of symmetry. 



Each of these will be discussed and illustrated, 

 (i) The arrangement of the parts upon the receptacle may be either 

 spiral, as in Adonis (Fig. 188) ; or cyclic, as in Ornithogalum (Fig. 187) ; 



Fig. 188. 



Floral diagram of Adonis. 

 (From Strasburger.) 



Fig. 189. 



Floral diagram of Helleborus. 

 Church.) 



(After 



or an intermediate condition [hemicyclic) may be found between them, 

 as in some of the Buttercup Family (Fig. 189). The cyclic type is 



