125 



qiiently, gronps of plants who33 cliaracteristica mostly occur in correlation are less 

 changeabls ; while groups of plants whoss characteristics usually occur indepen- 

 dently are more changeable. Such famihes as the Orchidacese and Graminea} 

 belong to the former, while such as the Loganiacege and Myoporaceae approach 

 the latter class. 



What he state in §§ 21 and 22 is, in brief, that on one hand he regards 

 characteristics in linkage - relation as those denoting the serial orders of advance- 

 ment and gives them a high systematic importance, but on the other hand 

 he puts no value on the characfceristics which occur independently and without 

 regard to others. But, in this I cannot concur. In my opinion, we ought 

 to take into consideration for classificatiou all characters without being partial 

 to any of them. 



The perianth characters to which he refers in § 23'^ are the most important, 

 as far as present systematic botany is omcerned. But when we ask why 

 they are so appreciated, no reason is forfchcoming. There is nothiug but con- 

 vention to supporfc the pracfcice, as I have already explained. 



In § 24 he says : — 



Mit Ausnahme sehr weniger Falle liegt bei den Angiospermen klar zutage, daB 

 clie Formen mit Zwitterbliiten phylogenetisch Slter sincl, als die sonst sich gleich 

 verhaltenden mit eingeschlechtlichen Bliiten. Diese Progression tritt unendlich 

 oft ein tmd ist zur Gruppenbildimg kaum zti verwerten. 



But why is it that the characters of bisexual or unisexual flowers that show, 

 as he expresses it, a serial advancement can not be appreciated as having 

 high sysfcematic vahie ? This is, in my opinion, only because of insisting upou 

 a static system. According to the dynamic view of a system, there can be 

 no character that can not be so appreciated. 



In §§ 25 and 26'^ he refers to many characters showing serial progression. 

 He puts systematic vahie on some of these, but not on some others. But 

 what is the reason of such partial treatment of charactei-s? It is, as far as 

 I can judge, merely because of an unquestioning acceptance of the present 

 static system, which would of course at once be ^dohited by the fair apprecia- 

 tiou of aU characters. 



1) EsoLBB, A. — .1. c. p. XVL 2) ENai.s!B, A.— i. c. p. XVIIL 



