120 



which we may take this character at one time or that at another. On the 

 other hand, groups shown in the first half of the same quotation are charac- 

 terized by many characters (by these and at the same time also by those) ; 

 their limits and members do not change so manifestly as in the case of the 

 former groups, although the characters taken as standards vary. Spaaking 

 enerallv, there are, to be sure, some groups which are more dynamic and 

 others which are less dynamic. For examples, the Velloziacese, Loganiacese, 

 Myoporacese, Labiatae, Verbeuaceae, Euphorbiacese are more dynamic ; while 

 the Gramineffi, Orchidacese are less dynamic groups. The latter certainly are 

 unchangeable within the limits of the variation of certain criteria ; but they 

 can not be exempted from being more or less dynamic, when all considerations 

 known as well as unknown to us are taken into account, as we shall see 

 later on in the dynamic system and the explanation of it, to be given in this 

 paper. 



Now, let us take tha words, dynamic and static, in a comparative sense 

 and by " static " let us mean what is less dynamic. Then, there are two ways 

 of expressing the standing of all groups, namely : 1, to regard all groups as 

 static forms, and treat dynamic forms as exceptional cases ; 2, to regard all 

 groups as dynamic forms and to treat static forms as exceptions. Of these 

 two methods, the latter seems to me to be preferable to the former. The 

 reasonableness of my preference AVI 11 be seen when we come to explain the 

 dynamic system. Spaaking generally, what I call a less dynamic group is 

 mostly represented by groups of the lower class, such as species or genera, 

 and what I call the more dynamic is illustrated by groups of the higher 

 class, such as families or series. Such groups as the Orchidaceee and 

 Grammes, just given as examples of less dynamic groups, somewhat correspond 

 to what we would have regarded as genera or the like, when compared with 

 more dynamic groups such as the Euphorbiaceas or Myoporacese. 



What ENGLER says in 4, may be taken as an illustration of the in- 

 constancy of groups. In 7, he goes on to say : 



Die Erfahrong, claS einzelne Merkmale zur Charakterisiemng grofierer Pflanzen- 

 gemeinscliaften venvenrlet werden konnen, anclere nicht, fuhrte zu der Aimahme von 



1) ENGLEB, A. 1. c. p. XI. 



