44 ] The Classification of Lower Organisms 



Family 4. Schizogoniacea [Schizogoniaceae] Chodat. Family Prasiolaceae West. 

 Family Blastosporaceae Wille. Filamemous or thallose algae, freshwater or marine, 

 of the structure of Porphyrea, but of a green color; sexual reproduction unknown. 

 Kylin (1930) found the pigmentation to be that of green algae rather than of red. 

 Copeland (1955) was unable to discern nuclei. The sole genus Prasiola {Schizo- 

 gonium represents a stage of development) is of about fifteen species. Setchell and 

 Gardner (1920) and Ishikawa (1921) suggested the place in Bangiacea here given to 

 this group. 



Family 5. Compsopogonacea [Compsopogonaceae] Schmitz in Engler and Prantl 

 Nat. Pflenzenfam. I Teil, Abt. 2: 318 (1896). Family Erythrotrichiaceae Smith 

 Freshw. Algae 122 (1933). Filaments, unbranched or branched, uniseriate or pluri- 

 seriate, or thalli. Spore-formation is accomplished by the division of a vegetative cell, 

 by an oblique wall, into two unequal cells; the protoplast of the smaller is released as 

 a spore. Rosenvinge observed the spores of Erythrotrichia cornea to move as far as 

 140[i per minute. Sexual reproduction is much as in Porphyrea. Erythrotrichia. 

 Erythrocladia. Compsopogon, in fresh water, the cells with numerous parietal plastids. 



Class 2. HETEROCARPEA Kutzing 



Class Heterocarpeae Kiitzing Phyc. Gen. 369 (1843). 



Class Florideae (C. Agardh) J. Agardh Sp. Alg. 1 : v ( 1848). 



Subclass Florideae Engler in Engler and Prantl Nat. Pflanzenfam. I Teil, Abt. 2: 

 ix (1897). 



Subclass Euflorideae de Toni Sylloge Algarum 4: 4 (1897). 



Abtheilung (of Stamm Rhodophyta) Floridineae Pascher in Beih. bot. Centralbl. 

 48, Abt." 2: 328 (1931). 



As this is the type group of phylum Rhodophyta, most of the synonymy of that 

 name applies to this one also. 



Red algae whose bodies consist essentially of filaments growing apically, the cells 

 with protoplasmic interconnections, the plastids (except in some of the lowest ex- 

 amples) of the form of multiple parietal disks; the filaments commonly compacted 

 into cylindrical or thallose bodies; zygotes not dividing to form spores directly, pro- 

 ducing spores by budding or indirectly by processes of growth of various degrees of 

 complexity. 



In undertaking to describe the varied, and often highly complicated, reproductive 

 processes of the typical red algae, one notes that these organisms occur as haploid 

 individuals, and that the majority occur as distinct male and female haploid individ- 

 uals. Sperms (commonly called spermatia) are minute naked protoplasts released 

 from small cells commonly occurring in patches on the surfaces of thalli. The egg 

 is called a carpogonium (Schmitz, 1883). It is the terminal cell of a specialized fila- 

 ment, the carpogonial filament, and bears a filiform terminal extension, the tri- 

 chogyne (Bornet and Thuret, 1867), whose function is to receive the sperms. The 

 cell, often diflferentiatcd, from which the carpogonial filament grows, is the support- 

 ing cell [Trugzelle). 



In the more primitive members of the class, the zygote gives rise by budding to a 

 mass of cells called the cystocarp. The cells of the cystocarp release their protoplasts 

 as spores called carpospores. These on germination produce haploid individuals like 

 the original ones. The zygote nucleus is the only diploid nucleus in the life cycle; its 

 first divisions arc meiotic. 



