THE FIGWORT FAMILY. 227 



II. State concisely, and in general terms, what charac- 

 ters you have found to be common to all the species 

 studied. 



There is evidence that the Scrophulariacese are an old 

 family of plants, and one that may fairly be reckoned to 

 have gained a place among the dominant groups. There 

 are nearly two thousand species distributed over the entire 

 globe. While well marked as regards family characters, 

 the different genera and species exhibit very wide diver- 

 gence of structure, often associated with peculiarities of 

 color that stand in evident relation to the insects on which 

 they have come to depend. A considerable number have 

 entirely lost the capacity for self-fertilization, and the 

 mechanical arrangements are in some cases so complicated 

 as to be difficult of explanation. The gradation of forms 

 from comparatively simple ones to others that show 

 remarkable adaptations to highly specialized insects, offers 

 a peculiarly interesting study of developmental history. 1 



SPECIAL STUDIES. 



I. Morphology of the flower of the Scrophulariacese. 

 II. Peloria in this family and its significance. 



III. Comparison of mechanisms by which fertilization is 



effected in different genera of Scrophulariacese. 



IV. Exclusion of unbidden guests as accomplished in 



Pentstemon and other genera. 



V. The genus Veronica. A comparison of different 

 species of the genus, and of the genus itself with 

 other representatives of the family. 

 1 Cf . Mtiller, Fertilization of Flowers, pp. 429-465. 



