128 



To sum up what we have so far discussed, Engler's principles are tliose 

 of tlie present static system, but the facts so far he has given them plainly 

 show tliat the latter system is not quaHfied to express all the natural relatious 

 and that it should be a dynamic system that we ought to contemplate. 



b. Engler's explanation of the synopsis of the 

 Embryophyta siphonogama^'. 



Here let us consider at some length what we liave discussed in the foregoing 

 pages. Engler refers in p. 359 in his work to the calazogamy and states that 

 it has no great systematic vahie, the only reason for this being that it does 

 not come in correlation with other characters. In my judgement, however, 

 various behaviors of pollen-tubes in diiferent plants show some relations in 

 that resp3ct; tliis ought to be taken into the consideration in classification. 

 It may prove to be inconvenient in the static system, but it does no harm 

 in making a dynamic system. Then, he refers to Van Tieghem's system^^ 

 and puts no great importance on it. But I think that Van Tieghem's system 

 is right in that respect, although in that respect only. In a dynamic system 

 it would be regarded as an impoi-tant phase. 



As to the Monocotyledons'^^ he makes the following statement*^ : — 



icih habe gezeigt, dass tmter den Monokotyledoneen zunlichst Reihen existieren, 

 bei denen in der ZaM der Bliitenteile Unbestiindigkeit herrscht, waLrend andere voll- 

 standige oder reducierte pentacyklische Bliiten besitzen. Anf der ersten Stufe stehen 

 diejenigen Eeihen, bei welchen noch voUkommen achlamydeische Bliiten vorkommen. 

 Es sind dies die Fandanales, Helobice und Glumijiora;. 



Thus, he divides the Monocotyledons into two, according as whether the 

 number of the floral elements is deiinite or indefinite. This is indeed one way 

 of dividing, yet there are many others. Their natural relations will not be 

 understood, till we divide and group them in several different ways. To learn 



1) EsGLEK, A. — Erlauterungen zu der tjbersicht iiber die Embryophyta siphonogama, in 

 der Natiirl. Pfl.-fam. Nacht. L pp. 358-380, (1897). 



2) Rendle, A. B. — The Classification of Flowering Plants, L p. 2">, (1904). 



3j Here I must call readers' attention to the fact that there are some indicatioas of a 

 second cotyledon in certain of the grasses, such as Zivmvn, Avena, etc. — Jeffrey, E. C. — ^The 

 Anatomy of Woody Plants (Chicago, 1917) p. 377. 



4) Ekglbb, A. — Erliluterungen, 1. c. p. 360. 



