1917 



Muenscher; Key to Phaeophyceae 



281 



On rocks in the littoral zone on surf-beaten shores about Cape Flat- 

 tery. A number of good specimens were dredged five fathoms below low 

 tide in Peavine Pass between Blakely and Obstruction Island in July, 

 1916. 



34. DILOPHUS J. Agardh 



1. DiLOPHUs FLABELLATUS Collins, in Collius^ Holden & Setchell's Phy- 

 eotheca Boreali-Americana, 834. Fig. 46 



Plant body rounded in outline, composed of a densely dichtomously 

 branched flattened thallus ; branches or segments of the thallus elongate, 

 widening upwards, with entire margin and forked or rounded tips. Young 

 plants consisting of a single layer of large cells with a single layer of 

 small cortical cells, older plants becoming thicker especially near the 

 margin. Oogonia, antheridia and spores on separate individuals, at first 

 on the middle of the segments, later covering the entire width ; oogonia 

 scattered but usually close; antheridia in oval or oblong patches; spores 

 in patches, sometimes becoming confluent. 



47 



Chordaria abietina 



48 



Castagnea divaricata 



PLATE 66 



Fig. 47. Plant with pad-like holdfast. X 0.25. 



Fig. 48. a, Part of cross section of branch ; s, unilocular sporangia ; 

 h, hyaline hairs ; c, cortical filaments with terminal round cells ; X about 

 200. b. Portion of plant; X 0.5. 



