1922] Setchell-Gardner : Phycological Contributions 337 



measurements of the original. De-Toni (1895, p. 582) gives 35/* to 70/x 

 as the height and 7,/x to 12/x as the width of the gametangia. In height 

 of gametangia our form approximates to forma seriata Reinke (1889, 

 p. 46) , but has no true hairs so far as we have ever been able to observe 

 from the examination of many specimens from different localities. 



At times the individuals are very numerous on the host, so much so 

 as to interfere with each other's growth. In one collection (Gardner, 

 no. 4651) they are completely confluent over several square inches, and 

 the outline of the individuals can be detected only by staining and hy 

 microscopic examination. 



Myrionema foecundum f. subulatum forma nov. 



Plate 33, figures 1-3 



Filamentis basalibus per ramulos numerosos, subulatos, 2-4 cellulis 

 compositos, inter cellulas hospitis penetrantes annectis; zoosporangiis, 

 "ascocystis" et pilis veris ignotis. 



Growing on the sporophylls of Nereocystis Luctkeana. Near the 

 "Cliff House," San Francisco, California. Type, Gardner, no. 4651 

 (Herb. Univ. Calif., no. 207028), November. 



Forma subulatum is very similar to forma simplicissimiim. The 

 gametangia average slightly larger, and are usually more blunt. There 

 are no so-called "ascocysts" present. The chief distinction is the 

 presence in this form of numerous awl-shaped rhizoids, found in no 

 other form of the species, so far as we have been able to ascertain. 



Myrionema foecundum f . ramulosum forma nov. 

 Plate 33, figure 8 



Frondibus pulvinulos parvos, orbiculares, 1-3 mm. diam. forman- 

 tibus ; filamentis erectis superne sparse ramosis, 55-65/a longis ; cellulis 

 filamentorum erectorum 5.5-6.5/t diam. quadratis, cellulis terminalibus 

 frequenter 2-3-plo longioribus quam latis; zoosporangiis, "asco- 

 cystiis, ' ' et pilis veris ignotis ; filamentis erectis omnibus in gametangia 

 transformatis. 



Growing on the pneumatocysts of Nereocystis Luetkeana. Friday 

 Harbor, San Juan Island, Washington. Type, Gardner, no. 4065 

 (Herb. Univ. Calif., no. 207018), August. 



This form of 31. foecundum differs from the other forms of the 

 species in having secund "proliferations" near to the outer ends of- 

 many of the gametangia. 



