1886-87.] Affinities of Scrophulariaceoi. 99 



But that this inequality of growth throughout the parts 

 of the flower does not account for the disappearance of the 

 stamens in the majority of cases is evident when we notice 

 that the posterior stamen in most Scrophulariaceae (as in 

 Labiatffi) is on that side of the flower which develops first ; 

 the growth in most genera, as Payer has pointed out,* being 

 from the posterior to the anterior. 



Payer, in his Organogdnic has noticed it as a remark- 

 able thing, that whereas the growth in most flowers of the 

 order is thus from the posterior to the anterior, the lateral 

 stamens should be smaller than the anterior, and he further 

 expresses surprise that the lower petal in Veronica, the first 

 to develop, should be smaller than the upper, which is the 

 last. It is therefore evident that this unequal growth in 

 the developing flowers is not the chief cause, but that certain 

 of the stamens, especially in asymmetrical or bilabiate flowers, 

 are of more advantage than others, and therefore are developed 

 with the greatest certainty in the struggle for development, 

 which struggle is present, though on so small a scale, as surely 

 among the parts of the flower as elsewhere. 



The corolla affords much material for careful comparative 

 study, but it is to be doubted whether its modifications of 

 form can be regarded as indicating very definitely lines of re- 

 lationship among the genera. Being the attractive part of 

 the flower, it is most likely to be specialised, and this is seen 

 remarkably in Scliizantlius and Collinsia, where modifications 

 exist to aid in fertilisation, which remind one of those which 

 occur in Cytisus. Minor points may be made out, however, 

 as, for instance, where a small pouching in Antirrhinum, 

 which aids in fertilisation, may be connected with the more 

 or less conspicuous spurs in the different species of Linaria. 

 Again, in Verhascum, which is now recognised as the link 

 between this order and SolanacCiT, there is to be observed a 

 tendency to irregularity where the two upper petals are 

 generally smaller than the three lower. This irregularity in 

 tube or limb becomes more and more pronounced in Digitalis 

 and Mimulus, until finally it reaches a climax in the firmh' 

 shut lips of the personate limb of Antirrhinum and some 

 species of Linaria. 



* Traits iVorganogenia compane de la flcur. 



