[417] THE ALG^E l8l 



In the branches of Liebmannia sp. from Sitka (i42<5). 



A very minute plant the erect branches of which might easily be taken 

 for a part of the host plant. The penetrating filaments are 1-2 ft 

 wide, short, sparingly branched ; cross partitions few and inconspicu- 

 ous, at intervals closely applied to the host cells ; no hairs or unilocu- 

 lar sporangia were observed. 



Streblonema pacifica sp. nov. (Plate XLV, fig. la and i<5.) 



Plant composed of irregular branching horizontal threads, from 

 which arise mostly unicellular, haustoria-like filaments which pene- 

 trate into the host plant, and erect filaments arising at right angles to 

 the horizontal ones ; cells of the horizontal filaments 4-8 ^ wide, twice 

 as long as the diameter ; erect filaments short, unbranched or once di- 

 chotomous, 3070 fj. long, most of them bearing a narrow elliptical plu- 

 rilocular sporangium 5 fi and 13 At, which contains about five uniseriate 

 zoospores. The plant forms circular dark brown patches 2-4 mm. in 

 diameter on the sporophylls of Alaria. Related to Streblonema minu- 

 tulum of Heydrich, but larger in all its measurements. 

 Yakutat Bay (438). 



Streblonema irregularis sp. nov. (Plate XLV, fig. 2.) 



Plant consisting of irregularly branching surface filaments applied 

 closely to the host plant, from which arise numerous simple or spar- 

 ingly branched erect filaments 1-2 mm. high, 9-14 p wide, cells as 

 long to twice as long as broad ; from the surface filaments, filaments 

 10-14 fi wide, with cells a little shorter or longer than broad, penetrate 

 the substratum irregularly ; plurilocular sporangia linear, lanceolate or 

 ovate, terminal or lateral on the erect filament, 14-18 fi wide, 55-70 p 

 long ; no unilocular sporangia observed. 



Forming small brown patches on the bulbs of Nereocystis pria^us, 

 Sitka (164). 



This plant is closely related to Streblonema stilophorea in its gen- 

 eral appearance and method of branching, but differs from it in the 

 shape of the sporangia and the chromatophores of the vegetative fila- 

 ments which are small, round and numerous in this species. 



Ectocarpus tomentosus (Huds.) Lyngb. 



Abundant on Fucus evanescens, Sitka harbor (166), and Victoria, 

 British Columbia (49). 



The rope-like tufts of the Alaskan specimens are fully as long as 

 those from the Atlantic ocean, while the specimens from the Califor- 

 nia coast are rarely over three mm. in length. 



