BOT.-VOL. I.] SAUNDERS— PHYCOLOGICAL MEMOIRS. 15I 



menziesii, on the fruiting tips of Cystoseira osmundacece^ on 

 rocks, on Codiuni adhcerans and C. mucronatum Calif or- 

 nicuvi. Pacific Grove, California, 1895. 



The form on Cystoseira averages slightly larger and many 

 of the plurilocular sporangia arise directly from the creep- 

 ing filaments; no unilocular sporangia were found on this 

 form. In the forms that grow on a hard substratum, the 

 creeping filaments are short and form a compact network 

 on the surface ; in those that grow on a soft substlratum 

 {C odium, etc.) the creeping filaments are much elongated 

 and ramify between the loose threads of the host plant. 



II. Ectocarpus hemisphericus, sp. nov. 



Plate XVII. 



Plant densely tufted, arising from a compact network of creeping filaments. 

 Erect filaments unbranched at base, primary branches dichotomous, diver- 

 gent, long, not at all narrowed upward, ending bluntly above, secondary 

 branches numerous, short, clustered, many of them ending in a short, blunt 

 hair ; cells at base 15-20/x broad, 2-3 times as long as the diameter, above 

 22-3o,« broad, 1-2 times as long as the diameter, slightly constricted at the 

 joints ; chromatophores small, numerous, linear or disk-shaped ; plurilocular 

 sporangia lanceolate or ovate, obtuse, short, 30-90/^ x 14-20/i (rarely 30// 

 long), borne laterally on a short stalk in the upper part of the filament; uniloc- 

 ular sporangia short, cylindrical, 30-35/^ x 2o-25,a, on a one-celled stalk, on 

 the same filament with the plurilocular sporangia. 



The plant is very abundant, forming dense, hemispherical 

 tufts 2-4 mm. high on Pelvetia fastigiata and Taonia lenne- 

 backercB. San Pedro, California, Aug., 1896. 



But one specimen was found of the form on T. leniie- 

 h acker cB. 



12. Ectocarpus hemisphericus minor, form. nov. 



Plate XVIII, Figs. 1-3. 

 Vegetative filaments simple or but slightly branched, 16-21/1 broad. 



The plant forms small, dark brown tufts 1-2 mm. high 

 on the fruiting tips and upper branches of Fucus harvey- 

 atms. The whole plant is smaller and does not form the 

 dense rounded tufts as in the type. San Pedro, California, 

 Aug., 1896. 



