Laing. — On the Classification of the Algae. 299 



Art. XLVIII. — On the Classification of the Algae. 

 By R. M. Laing, M.A. 

 [Read before the Philosophical Institute of Canterbury, 6th August, 1885.] 



Plate Xa. 

 Many attempts to classify the Alga have been made, and though 

 of late years our knowledge of this division of plants has greatly 

 increased, yet it cannot be said that their relationships to each 

 other have been satisfactorily made out. The older botanists 

 were content with dividing them into two genera, Conferva in- 

 cluding all fresh, and Fucus including all salt water forms. 

 Harvey was the first to divide them into three groups, according 

 to the supposed colour of their spores, thus : Chlorospermea 

 (green-spored), Melanospermea (olive-spored), Bhodospermea (red- 

 spored). In these divisions he has been followed by Sir J. D. 

 Hooker, up to the present day. 



Decaisne divided the Alga into Symporea (united spores, the 

 modern Conjugated) , Aplosporea (spores simple, not motile, 

 green or brown), Choristosporea (separated spores, motionless, 

 red, developed in fours). The next classification was that of 

 Thuret; his divisions are well known: (1.) Zoospore®, (2.) 

 Chlorosporea, (3.) Phaosporea, (4.) Fucacea, and (5.) Floridea. 

 In 1872, Cohn proposed to abolish the distinction between Alga 

 and Fungi, and form them into parallel lines. In 1875, Sachs 

 said the classification of the Alga, was in the utmost confusion. 

 He gave a new classification, improved upon in 1882, grouping 

 the different divisions of the Alga, thus : — 



Class A. — Protophyta. • 



I. Cyanophycacea. 



(Phycochromacea, Prantl. 

 II. Palmellacea (in part). 



I Product of fertilization, 

 a resting spore. 



f 



( Product of fertilization, 

 a new individual. 



