120 Development of the Natural System under [BOOKI. 



Jussieu's division of the Cryptogams and Monocotyledons 

 offers much that is satisfactory, if we put the position of the 

 Naiades out of sight. The grouping of the Dicotyledons on the 

 contrary is to a great extent unsuccessful, chiefly owing to the 

 too great importance which he attached to the insertion of the 

 parts of the flowers, that is, to the hypogynous, perigynous, and 

 epigynous arrangement. It is in this grouping of families into 

 classes that the weak side of the system lies ; it is utterly 

 artificial, and the task of his successors has been to arrange the 

 families of the Phanerogams, which were most of them well- 

 established, and especially those of the Dicotyledons, in larger 

 natural groups. But this could not be effected, till morphology 

 opened new points of view for systematic botany; Jussieu, as 

 has been already remarked, accepted Linnaeus' views of the 

 morphology of the organs of fructification in Phanerogams, 

 though he introduced many improvements in details. He laid 

 greater stress on the number and relative positions of the 

 different parts of the flower ; attention to their insertion on the 

 flowering axis, which he designated as hypogynous, perigynous, 

 and epigynous, would have been a great step in advance, if he 

 had not overrated its systematic value. The morphology of 

 the fruit is very superficial in Jussieu ; even the designation of 

 dry indehiscent fruits as naked seeds recurs in his definitions, 



