1922] Setchell-Gardner : Phycological Contributions 343 



Myrionema compsonematoides sp. nov. 



Plate 34, figure 10 



Frondibus pulvinulos microscopicos linea exteriore irregulares, 

 200-400jU, diam. f ormantibus ; parte prostrata filamentis distortis com- 

 posita; filamentis erectis cyliiidricis, simplicibus TO-SO/a altis, pilis 

 veris ignotis; cellulis filamentorum repentium forma magnitudineque 

 aliquantum irregularibus, 4-6ju, diam. ; cellulis filamentorum ereetorum 

 cylindricis, 5-1 fx diam., quadratis; "ascocystis" sparses, terminalibus 

 aut prope basim filamentorum ereetorum lateralibus; gametangiis 

 fusiformibus usque ad clavatis, sessiJibus aut brevi-pedicellatis, 50-65/x 

 longis, 7-10/x latis; loculis inferne uniseriatis, superne biseriatis. 



Growing on the blade of Laminaria complanata. Friday Harbor, 

 Washington. Type, Gardner, no. 4118 (Herb. Univ. Calif., no. 207019), 

 August. 



Myrionema compsonematoides seems to be a modification of M. 

 foecundum. There is a slight sterilization of tissue in that a few of the 

 erect filaments remain sterile and develop slightly beyond the game- 

 tangia, and in that a part of the gametangia are pedicellate. It seems 

 to tend toward Compsonema in these respects, and in having biseriate 

 gametangia in part. 



Myrionema hecatonematoides sp. nov. 



Plate 34, figure 11 



Frondibus pulvinulos tenues dilute fuscos, linea exteriore irregu- 

 lares, usqve ad 6 mm. diam. f ormantibus; parte prostrata filamentis 

 distortis, irregulariter radiantibus composita, plerumque monostro- 

 matica, pro parte distromatiea, inferne ramulos radiciformes pene- 

 trantes, paxilliformes, paucos emittente; filamentis erectis simplicibus, 

 cylindricis, 240-260/1, longis; pilis veris deuntibus; cellulis filamen- 

 torum ereetorum 6.5-7.5ju, diam., 2-3-plo longioribus; zoosporangiis 

 ignotis ; gametangiis sessilibus aut in pedicellis 1-2-cellulis compositis 

 e filamentis repentibus oriundis suffultis, cylindricis usque ad fusi- 

 formibus, 45-55/A longis, 7-8. 5ja latis ; loculis plerumque uniseriatis, in 

 parte latiore gametangiorum biseriatis. 



Growing on the pneumatocysts of Nereocystis Luetkeana. Pacific 

 Grove, California. Type, Gardner, no. 4533 (Herb. Univ. Calif., no. 

 207025), December. 



As indicated by the partial distromatic base, the slight tendency to 

 biseriate loculi in the gametangia and the sterilization of a part of the 

 erect filaments, this species of Myrionema seems to be differentiating 

 in the direction of the genus Hecatonema. We are retaining it in the 

 genus Myrionema because of a preponderance in number of uniseriate 

 loculi and monostromatic filaments in the prostrate portion. 



