236 



the plants of the world as a whole. The main groups adopted 

 were Myxothallophyta, Euthallophyta, Embryophyta zoidio- 

 gama (Bryophyta and Pteridophyta), and Embryophyta siphono- 

 gama (Gymnospermae and Angiospermae) . Later in the Syllabus 

 der Pflanzenfamilien the Thallophyta have been broken up into 

 many groups. The angiosperms are arranged as follows: 



Monocotyledoneae: First, plants with the number of floral 

 parts indefinite, as in the arrowhead; then those with the number 

 definite, as in the lily. 



DicoTYLEDONEAE : ArcMchlamydeae, petals none or separate. 

 First, Casuarina and other plants with perianth absent or single : 

 mostly catkin-bearing, wind-pollinated trees, as oak. Under 

 flowers with distinct calyx and corolla come those with axis-like 

 receptacle, such as buttercup, and those with cup-like recep- 

 tacle, as rose; last, those with inferior ovary, as evening primrose. 



Metachlamydeae, petals united, grouped by the number of 

 staminate whorls and the position of the ovary. 



"Engler has evidently abandoned the attempt to produce a 

 phylogenetic system," says Lotsy, " and has been content to 

 establish a readily understood morphological system of the plant 

 world which may be the least affected by constantly changing 

 phylogenetic views." 



With the completion of the Pflanzenfamilien botanists had 

 for the first time available an extensive connected account of all 

 groups of plants, a fact which has brought to the system there 

 adopted wide international sanction. Minor changes have been 

 introduced in successive editions of the Syllabus. 



Recent Studies 



A few developments of recent years, of special interest, may 

 be mentioned. With the spread of the doctrine of evolution has 

 grown the ideal of a single system, a truly natural classification 

 of plants and animals which shall exhibit the course of evolution 

 of the forms of life on the earth. 



Bower has given reasons to show that eusporangiate ferns, such 

 as Marattia and Botrychiiim, must be considered more primitive 

 than the leptosporangiate forms, such as Polypodiaceae, a \iew 



