(EDOGONIUM. 



[ 552 ] 



CEDOGONIUM. 



of a zoospore, which moves with the aid of 

 a crown of cilia. Alter a time the motion 

 ceases, the cilia disappear, and one end of 

 the zoospore becomes elongated into a root 

 like the ordinary zoos]wres. The little cell 

 thus fixed becomes di\ided bj a transverse 

 septum. Each spore thus produces four 

 CEdof/onmm plants. 



The antheridial structures of the CEdo- 

 gonia are either formed in the ordinary fila- 

 ments (PI. 5. fig. 13), or from dv\ arf fila- 

 ments produced from the smaller zoospores 

 or androspores (PI. 5. fig. 10). In either 

 case they consist of one or more very short 

 joints of the filament, formed in the ordi- 

 nary way, the contents of which divide 

 into two portions. The cells then dehisce 

 and allow the new products to escape, which 

 resemble the vegetative zoospores, but are 

 much smaller. These new bodies, the 

 spermatozoids, make their way through the 

 orifices in the parent cells of the spores and 

 fertilize their contents (PL o. fig. 20). 



Some of the larger spermatozoids move 

 like Amahce, creeping over the oospore, 

 until they I'each the canal, into which 

 they enter. 



The Qidogonia appear to be sometimes 

 purely monoecious or dioecious, the single 

 filaments including eitlier both antheridial 

 and spore-cells, or only one kind of organ ; 

 bat the most common condition is interme- 

 diate : the filaments having some joints 

 converted into sporangial cells, others 

 giving birth to the androspores, which 

 germinate into dwarf antheridial filaments, 

 often sessile on or near the sporanges, 

 which produce spermatozoids. This con- 

 dition is termed bj' Pringsheim gynandro- 



Sj}07'OUS. 



The systematic arrangement of the 

 species is difficult on account of the vari- 

 ability in the size of the filaments. Prings- 

 heim makes the following arrangement: — 



* Spores globular. 

 t Sporanges opening by a valvular lid. 



CE. rostellatum. Sporange oval, spore 

 globular, not filling the sporange, An- 

 theridia 3- or 4-celled. Monoecious. 



tt Sporanges opening by a lateral orifice. 

 \ Monoccions. 



(E. curvum. Sporanges depressed, orifice 

 in the middle line ; spores completely 

 filling the sporanges, and of the same form. 

 Antheridia 3- and 4-celled. 



(E. tumiduhtm. Sporange ovate, orifice 

 in the upper half; spore globular, not 

 fillinof the sporange. Antheridia mostly 

 2-ceUed. 



XX Gynandrospurous. 



CE. Rothii. Dwarf male plant straight, 

 sessile on the sporange, without a spreading 

 base. Sporange ovate, expanded in the 

 middle ; orifice in the middle line ; spores 

 depr£ssed, filling the inflated part of the 

 sporange. 



GL. depressum. Male plant straight, sessile 

 on the sporange, with a foot and internal 

 1-celled antheridia. Sporange depressed, 

 orifice in the middle line ; spores of the 

 form of the spoi-ange. not filling it. 



CE. Braunii. Male plant curved, with a 

 foot and 1-celled antheridium. Sporange 

 oval, iuflated in the middle ; spore globular, 

 not filling the sporange. 



CE. ecliinospermnnt. Male plant almost 

 straight, sessile on the cell below the 

 sporange, with foot and outer 1-celled an- 

 theridium. Sporange oval, orifice in the 

 lower half: spore globular, spinous. 



** Spores oval. 



t Sporanges opening by a circular lid. 



X Gynandrosjjorous, 



CE. ciliafinn. Male curved, sessile on the 

 sporange, with foot and outer 1-celled 

 sporangium. Spores oval, filling the broken 

 portion of the sporange. 



tt Sjwranges opening by n lateral orifce. 

 X Ciynandrosporous. 



CE. apophysatvm. Male plant curvid, 

 sessile below the sporange, and outer 2- 

 ranked antheridium. Sporange oval, orifice 

 in the upper half; spore filling the sporange 

 up to the cap-like part. 



XX Dioecious. 



CE. gomellipariuni. Male plants more 

 slender than the female ; anthei'idia monv- 

 rowed ; septa of the parent cells perpen- 

 dicular to the other cell-septa. Sporange 

 oval, orifice in the upper half, the spore 

 filling it completely to the cap-portion. 

 Filaments ending in seA'eral almost hyaline 

 elongated cells, without a terminal bristle. 



BiBL. Mohl, Bot. Ze.it. xiii. 689 ; De Bary, 

 Soc. Sc. Nat. Fribotire/, 1856 ; Carter, Ann. 

 N. II. 3 ser. i. 29 ; Ilassall,'^/^. 195 : Eraun, 

 Kiitz. Sp. Alg.; Eabenh. Alg. iii. 347; 

 Juranyi, Pringshei7ns Jahrb. 1873 ; Prings- 



