NEW FORMS OF OEDOGONIUM* 



L. H. Tiffany, 

 Ohio State University. 



Some algal collections made from lakes in the vicinity of 

 Akron, Ohio, in the summer of 1920 contained a species and a 

 variety of Oedogonium apparently undescribed. In accordance 

 with the rules of the Vienna Congress a Latin and an English 

 diagnosis of each is given. 



Oedogonium exocostatum nov. sp. 



Oedogonium dioicum; macrandrium; oogoniis singulis vel binis, 

 ellipsoideis vel globoso-ellipsoideis, rarius terminalis; poro superiore 

 apertis; oosporis eadem forma ac oogoniis, hasc plane complentibus, 

 membrana duplici ; episporio longitudinaliter costato (in sectione optica 

 transversal! undulato), costis integris, raro anastomosantibus, in medio 

 oosporae circa 13-15, endosporio Isevi; cellulis suffultoriis tumidis; 

 plantis masculis paululo gracilioribus quam femineis; antheridiis 3-7 

 cellularibus ; spermatozoidis binis, divisione horizontalis ; cellula fili 

 basali forma, ut vulgo elongata; 



Crassit. cell. veg. plant, fern. (13-) 18-25 ^ altit. 72-140 m 

 Crassit. cell. veg. plant, masc. (13-) 16-20 fx altit. 48-100 fj. 

 Cras.sit. cell. suff. 22-30 u altit. 60-90. m 



Crassit. oog. 40-52 /u altit. 68-96 m 



Crassit. oos. 38-41 m altit. 60-68 ^ 



Crassit. cell, antherid. ] 2-16 ju altit. 7-12 ^ 



Dioecious, macrandrous, oogonia single or often two, ellipsoid to 

 ellipsoid-globose, occasionally terminal, pore superior; oospores of the 

 same form as the oogonia which they very nearly completely fill, mem- 

 brane double; the outer spore wall marked by 13-15 longitudinal ribs, 

 inner wall smooth ; suffultory cells swollen ; male filaments a little more 

 slender than the female, antheridia 3-7 celled, sperms two, division 

 horizontal; basal cells elongate. 



Diam. veg. cells, female plant (13-) 18-25 m length 72-140 fx 



Diam. veg. cells, male plant (13-) 16-20 ^ length 48-100 m 



Diam. suffultory cells 22-30 n length 60-90 m 



Diam. oogonia 40-52 m length 68-96 m 



Diam. oospores 38-41 ^ length 60-68 n 



Diam. antheridial cells 12-16// length 7-12 n 



* Papers from the Department of Botan^', Ohio State University, No. 128. 



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