258 MORPHOLOGY OF ANGIOSPERMS 



eleven families from Xolanaceae to Globulariaceae, grouping 

 about the Solanaceae and Scrophulariaceae. This series con- 

 nects with the ('(hi ml vulus forms through the Xolanaceae, but 

 does not develop its carpel-structures as do the Borrage and 

 Labiate lines, retaining capsules with numerous ovules, but 

 there is a strong development of zygomorphy. 



To summarize at this point, the primitive stock of the series 

 seems to be the Convolvulaceae-Polemoniaceae alliance, from 

 which three distinct lines of development have diverged : the 

 Hydrophyllaceae-Borraginaceae line, with its modified carpel- 

 structures ; the Verbenaeeae-Labiatae line, with its modified 

 carpel-structures and zygomorphy; and the Xolanaceae-Globu- 

 lariaceae line, with its zygomorphy. It should be noted in pass- 

 ing that the zygomorphy is associated with a strong tendency 

 to reduce the number of stamens. 



The three remaining families are so peculiar in certain fea- 

 tures that Engler regards them as representing separate lines of 

 development, although the Acanthaceae are not easily separated 

 from certain families of the last alliance. The Myoporaceae 

 seem to be a reduced type with no clear affinities ; and the 

 Phrymaceae, with their achenes and orthotropous ovules, have 

 no evident connections in this alliance, in which their strong 

 zygomorphy has retained them. 



It would be our judgment, therefore, to break up this great 

 alliance of Tubiflorales into at least four, which might be called 

 the Polemoniales (Convolvulaceae and Polemoniaceae), Bor- 

 raginales (Ilydrophyllaceae and Borraginaceae), Labiatales 

 (Verbenaceae and Labiatae), and Personales (Xolanaceae, 

 Solanaceae, Scrophulariaceae, Bignoniaeeae, Acanthaceae, Pe- 

 daliaceae, Martyniaceae, Orobanchaceae, Gesneriaceae, Colu- 

 melliaceae, Lentibulariaceae, and Globular iaceae), the Myo- 

 poraceae and Phrymaceae being left undetermined or regarded 

 as reduction forms of Personales. 



VL Plaxtaoixat.es. — This includes the single family 

 Plantaginaceae with about 200 species. This family, with its 

 peculiar habit, 4-merous flowers, membranous corolla, and char- 

 acteristic fruit, is certainly entitled to special consideration. 

 If such a series as Tubiflorales be maintained, however, there 

 is no good reason why Plantaginaceae should not form one of 

 the seven or eight sections of it. If, on the other hand, the 



