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ALGOLOGICAL NOTES.— X.-XIII. 

 By G. S. West, M.A., D.Sc. F.L.S. 



(Continued from p. 89.) 

 X. — Observations upon Two Species of (Edogonium, with 



SOME EeMARKS upon THE OrIGIN OF THE DwARF MaLES. 



The two following species of (Edogonktm, both of rare occur- 

 rence, have each presented features worthy of special comment. 



1. (Edogonium rivulare (Le 01.) A. Br. ; Wittr. Prodr. 

 Monogr. (Edog. 1874, p. 36 ; Hirn in Acta Soc. Scient. Fennicae, 

 xxvii. 1900, p. 119, t. 12, f. 66. 



Crass, cell, veget. (plant. $ ) 37-39 /x ; altit. 4-6-plo major ; 

 (plant. (^) 29-33 /x; „ 5-7 „ 

 „ oogon. 75-77 /x; „ 128-137 i^; 



oospor. 59-67 /x; ,, 67-78 /x; 



„ cell, antherid. 24-26 /x ; „ 15-20 /x. 



Hah. Sutton Park, Warwickshire. 



There has not been a definite instance of the previous occur- 

 rence of this species in the British Islands, although it is recorded 

 for " Scotland " in Cooke's Brit. Freshw. Algae, p. 169. The 

 characters of the Warwickshire plants were typical in every 

 respect, although the oogonia were in all cases solitary, whereas 

 in various European and American specimens they are frequently 

 2-7-seriate. The wall of the oogonium also turned a rich golden- 

 brown during the ripening of the oospore, but this colouration 

 may have been due entirely to local circumstances. 



This Alga has been abundant in a small bay in Bracebridge 

 Pool, Sutton Park, attached to, and amongst, the submerged parts 

 of the shoots of Equisetum limosum, since 1906, but was propagated 

 only asexually up to the wet summer of 1910, when the sexual 

 organs were developed in abundance. It has also remained 

 sterile from September, 1910, to August, 1912. It produced 

 zoogonidia in immense quantities every year in the month of 

 October. This formation of zoogonidia was sometimes so active 

 that three generations consisting of no more than three cells, two 

 empty zoogonidangia of the first and second generations respec- 

 tively, and the escaped zoogonidium of the third generation, were 

 frequently observed. (Fig. 1, A.) 



2. (Edogonium fonticola A1. Braun in Kiitz. Spec. Alg. 1849, 

 p. 368 ; Wittr. Prodr. Monogr. (Edog. 1874, p. 41 ; Hirn, /. c. 

 p. 313, t. 49, f. 315. 



Crass, cell, veget. 22-25 /x ; altit. f-l|-plo major ; 

 oogon. 40-45 /x; „ 44-48 /x ; 

 ,, oospor. 38-43 (x ; ,, 42-46 /x. 

 Hah. Henley-in-Arden, Warwickshire. (June, 1910.) 

 This species occurred on stones in a small stream, and 

 although the specimens were in a state of fructification, I am 

 able to add little to our defective knowledge of the species. 

 Simultaneously with the development of oogonia and oospheres, 

 Journal of Botany. — Vol. 50. [Nov. 1912.] 2 a 



