SAPROLEGNIALES 815 



Eurychasma DiCKSONii (Wright) Magnus 



Hedwigia, 44: 347. 1905 



(Fig. 61, p. 818) 



Rhizophydium dicksonii Wright, Trans. R. Irish Acad. Dublin (Sci.), 26: 374, 



pi. 6. 1879. 

 Olpidium dicksonii (Wright) Wille, Vidensk. Selsk. Skr. Christiana (Mat.- 



Nat. Kl.), 1899, No. 3: 2. 

 Ectrogella dicksonii (Wright) ScherfTel, Arch. Protistenk., 52: 4. 1925. 



Sporangium at maturity generally protruding from the host cell, 

 extremely variable in shape and size, generally irregularly saccate, 25- 

 80 \x high by 20-40 \i in diameter, with one or two broad short discharge 

 tubes, wall thin, smooth, colorless; zoospores somewhat gibbose-pyri- 

 form, 5 [i. long by 3 \x in diameter, with two unequal, subapically attached, 

 oppositely directed flagella, emerging without encystment (?) or coming 

 to rest and encysting within the sporangium ("net sporangium"), from 

 which they eventually escape; resting spore not observed. 



Parasitic in Ectocarpus granulosus, Wright (loc. cit.), Ireland; Ecto- 

 carpus confervoides, E. crinitus, E. pusil/us, Hauck (1878:321), Italy; 

 Ectocarpus siliculosis, Rattray (1887: 589, pis. 147-148), Scotland; 

 Ectocarpus constanciae, Hariot (1889: 176), Kerguelen; Striaria atten- 

 uata, Wille (loc. cit.), Pylaiella littoralis, Lowenthal (1905:225, pi. 7, 

 figs. 3-7), Norway; Punctaria sp., Stictyosiphon tortilis, Pylaiella litto- 

 ralis, Ectocarpus sp., coll. K. Rosenvinge, Petersen (1905:476), Green- 

 land; Ectocarpus confervoides, coll. Borgesen, Petersen (1905:477), 

 Faroe Islands ; Ectocarpus sp., Stictyosiphon tortilis, coll. K. Rosenvinge, 

 Akinetospora sp., E. confervoides, E. sandrianus, Striaria attenuata, 

 Stictyosiphon tortilis, Pylaiella littoralis, Petersen (1905: 477, fig. VIII, 

 1-7), Striaria attenuata, Sparrow (1934c: 5, pi. 1, figs. A-S), Denmark; 

 Ectocarpus sp., Pierre Dangeard (1934: 69, pi. 8, figs. A-E), Stictyo- 

 siphon soriferus, Pierre Dangeard (1934), Ectocarpus sp., Aleem (1950d: 

 434, figs. 24-25), Ectocarpus sp., Pylaiella littoralis, J. Feldmann(1954: 

 133), France; Ectocarpus granulosus, Aleem (1950a: 239; 1950b:l 19, 

 fig. 1), Great Britain; Ectocarpus granulosus, Aleem (1950a: 239, figs., 

 1-9), Pylaiella littoralis, Striaria attenuata, Aleem (1953: 22, figs. 43-48, 

 pi. 2, fig. 3), Sweden. 



