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. Speaking 
generally, there are, to be sure, some groups which are more dynamic and 
others which are less dynamic. For examples, the Velloziaces, Loganiaces, 
Myoporacez, Labiate, Verbenacese, Euphorbiaceze are more dynamic; while 
the Graminex, Orchidacese are less dynamic groups. The latter certainly are 
unchangeable within the limits of the variation of certain criteria; but they 
can nos be exempted from being more or less dynamic, when all considerations 
known as well as unknown to us are taken into account, a3 we shall see 
later on in the dynamic system and the explanation of it, to be given in this 
paper. 
Now, let us take the words, dynamic and static, in a comparative sense 
and by “static” Jet 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 
group3 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 will be seen when we come to explain the 
dynamic system. Speaking 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 Orchidaces and 
Graminex, 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 Euphorbiacesw or Myoporaces. 
What EveLer says in §4, may be taken as an illustration of the in- 
constancy of groups. In § 7”, he goes on to say :— 
Die Erfahrung, da8 einzelne Merkmale zur Charakterisierang gréBerer Pflanzen- 
gemeinschaften verwendet werden kénnen, andere nicht, fuhrte za der Annahme von 
1) Enormr, A.—1L c. p. XL 
