182 ^ CENTURY Of PROGRESS IN THE NATURAL SCIENCES 



Harvey (1836) proposed the name Rhodospermeae for the red algae, which desig- 

 nation was changed to Rhodophyceae by Rnprecht (1851, 1855). Kiitzing (1843, 

 pp. 20, 21) suggested the names phycoerythrin and phycocyanin for the two 

 phycobilin pigments present in the plastids of these algae. (For summaries of 

 our knowledge of the pigments of red algae reference should be made to the 

 reviews by Kylin, 1937a, and Strain, 1951). 



Since present-day classification of the red algae is to a large degree based 

 on the details of development of the reproductive organs, emphasis will be placed 

 in this brief review on the growth of our knowledge of the reproductive processes 

 of the group. 



Ellis (1767) and C. Agardh (1828, pp. 57-58) referred to the clusters of 

 spermatangia as male reproductive organs. C. Agardh used the term antheridia 

 for those of Polysiphonia merely because of their superficial resemblance to an 

 anther. That they indeed were male structures was first established by Bornet 

 and Thuret (1866a, 1866b, 1867). 



That the same species of red alga may include two kinds of plants, each with 

 its own kind of spore-bearing structure (cystocarp and tetrasporangium) was 

 first emphasized by Stackhouse (1801, p. xxvi). At first. Turner (1802, pp. 293- 

 294) and others strongly opposed this view, believing that different species were 

 involved, but later Turner (1808, p. 130) remarked about this phenomenon 

 as follows: 



Of the zeal, with which the study of Marine Botany has been cultivated during the 

 few years that have elapsed subsequently to the publication of the Nereis Britannica 

 [by Stackhouse, 1795-1801], and the Synojysis of the British Fuci [by Turner, 1802], some 

 idea may be formed from the circumstance of the double fruit of F. [ucus] coccineus 

 l^Plocaviiiim vorciiieutn}, being at that time regarded as a curiosity, and as so extra- 

 ordinary to be in itself almost sufficient to justify the dividing of the plant into two 

 distinct species," whereas a similar appearance is now known to be observable in several 

 of its congeners, and we have every reason to believe, that in the course of time it will be 

 discovered in many others. 



In 1847 Harvey remarked (p. 4) : "The Ehodosperms are remarkable for 

 possessing what seems to be a double system of fructification, a thing without 

 parallel in the Vegetable Kingdom." On account of this feature, Kiitzing (1843) 

 had previously named them Heterocarpeae. 



Decaisne (1842a) considered the tetrasporangium as the "typical" reproduc- 

 tive organ of red algae and the cystocarp as a sort of proliferation or gemma. 

 Harvey (1849, pp. 67-74), on the contrary, was of the opinion (p. 73) that the 

 spores formed in the cystocarp should be considered ". . . of the nature of 

 seeds [that is, the result of a sexual process], and not as huds," and that the 

 spores formed in the tetrasporangium "should be regarded as gemmules." Be- 

 cause the clusters of spermatangia occur in a position similar to that of the 

 cystocarps in many genera of red algae (on trichoblasts in the Rhodomelaceae), 

 Harvey argued that these structures (the "antheridia" of C. Agardh) might be 

 of the nature of stamens. In the same work he remarked, however (p. 73) : 



... we do not yet know the cause of the formation of conceptacles [cystocarps] and the 

 production of spores. We know that seeds result from the joint agency of stamens and 



12. Turner (1802) had on this account divided it into two varieties and remarked 

 (p. 294), "There can indeed be but little question of their being in reality separate 

 species . . ." 



