Chap, iv Taxonomy, 1 860-1900 117 



each of these organs arises from a single cell, were grouped 

 together as Leptosporangiatae ; the rest, in which the 

 origin of the sporangium is multicellular, he called Eusporan- 

 giatae. 



Little further advance in classification of the lower plants 

 was made until the appearance of Eichler's system in 1883. 

 In this for the first time we find the recognition of three 

 of the four great groups which are generally recognized 

 to-day, the Thallophyta, Bryophyta, and Pteridophyta. 

 Eichler, however, grouped these together as Cryptogamae, 

 and regarded the latter as co-ordinate with the Phanero- 

 gamae. He abandoned Sachs' arrangement of the Fungi and 

 Algae as parallel series, and restored their rank as separate 

 classes, into which he divided his Thallophyta, while he 

 did not recognize the division Protophyta. It is in his 

 treatment of the Algae that we find perhaps the greatest 

 advance that his system presented. In it they were 

 divided into groups which were named according to their 

 colour — Cyanophyceae, Chlorophyceae, Phaeophyceae, and 

 Rhodophyceae. It was not, however, his intention to 

 indicate that in their colouring matter he found their 

 most characteristic feature. They fell into four natural 

 groups, each marked by very special features connected 

 with both their vegetative and their reproductive habit. 

 Each separate group was found, however, to possess a 

 distinguishing colour in addition to its other peculiarities, 

 and Eichler adopted this feature as a convenient one on 

 which to base its name. A fifth group, the Diatomeae, 

 was made by Eichler in his first scheme, but in the revised 

 proposals of 1891 it was united to the Phaeophyceae. 



Eichler's system was modified only slightly by Engler, 

 whose proposals were the latest that obtained acceptance 

 before the close of the century. He adopted in the main 

 the divisions of Eichler, though his subdivisions were not 

 quite the same. He made two divisions of the Thallophyta, 



