APPENDIX A 



531 



leaves. Each flower has a slender stalk, and consists of the following 

 parts : 



Calyx, sepals 4, slightly gamosepalous, inferior. Though the number 

 appears to be four, comparison with other species of Veronica, and with other 

 related plants, such as the Foxglove, shows that a fifth sepal, which should be 

 median and posterior, is here wanting. 



Corolla, petals' apparently four, gamopetalous, inferior, alternating with 

 the sepals and forming a wheel-shaped (rotate) corolla, which readily falls 

 away in one piece. Comparison with related plants shows that the large 



FIG. 437. 



Flower of Veronica chamaedrys, typically pentamerous : but the posterior sepal 

 is abortive : the two obliquely posterior petals are fully fused to form apparently 

 one ; only the two obliquely posterior stamens are developed. 



posterior petal is really the equivalent of two obliquely posterior petals fused 

 together. In front view the petals are marked by lines, or honey-guides, con- 

 verging to the centre of the flower. 



Androecium, stamens 2, epipetalous, diverging widely right and left. Com- 

 parison shows that these correspond to the two obliquely posterior stamens, 

 while those obliquely anterior are abortive, as well as the median posterior 

 stamen (Fig. 437). 



Gynoecium, carpels 2, antero-posterior, syncarpous, superior. The single 

 style projects between the diverging stamens, and bears a capitate stigma. 

 Ovary bilocular, ovules numerous, placentation axile. 



Fruit, a dry capsule. 



Pollination. The flower is a specialised and reduced example of the Scro- 

 phulariaceae. The change from a pentamerous to an apparently tetramerous 

 type follows from the abortion of the posterior stamen, which leads to abortion 

 of the posterior sepal and fusion of the two obliquely posterior petals. The 

 obliquely anterior stamens are also abortive, not being necessary for effective 



