1922] Setchell-Gardner : Phycological Conti-thutions 357 



sessilibus ant in pedicellis longioribus brevioribnsve, in filamentis 

 erectis secnndis, sessilibus pedicellatisve, aut rariore intercalaribus, 

 gametangiis terminalibus 60-100/a longis, 14-18/a latis, gametangiis 

 secnndis variabilibus, parvioribus. 



Growing on the pneumatocysts of Nereocystis Luetkeana. ]\Ioclips, 

 Washington. Type, Gardner, no. 3812 (Herb. Univ. Calif., no. 

 207037), May. 



Compsonema speciosum f. piliferum seems undoubtedly to be very 

 closely related to Myrionema speciosum Borgesen [1902, pp. 421-424, 

 which is the Hecatonema speciosum (Borgesen) Cotton, 1912, p. 15 

 (122) and the Hecatonema diffusum Kylin (cf. Cotton, loc. cit.)], 

 at least the two sets of plants agree very closely in general habit and 

 structure as described by Borgesen. Judging' alone from the descrip- 

 tion and figures the chief differences are that our plant has short 

 penetrating rhizoids, many terminal and no lateral hairs, and larger 

 gametangia. We are unable to say that the plant would produce 

 rhizoids on an uninjured host. The surface cells of the host are 

 destroyed under the epiphyte, and it is an open question whether the 

 penetrating rhizoids are or are not the cause of their death. Borgesen 

 does not give the dimensions of the whole plant, but he states that the 

 plants form short dense mats on the coneeptacles of Himanthalia lorea, 

 which would indicate that they were quite small. Our plants form 

 circular cushions or mats 5-8 mm. in diameter. Typical zoosporangia 

 were found at the ba»se of the erect j&laments. The lateral secund 

 gametangia standing nearly perpendicular to the filaments of which 

 the cell at the base in the filament becomes a part, is a character not 

 found in Compsonema gracilis Kuckuck. 



Compsonema sporangiiferum sp. nov. 



Plate 36, figures 3-8 



Frondibus pulvinulos orbiculares, 1-4 mm. diam. formantibus ; 

 parte prostrata filamentis compactis, irregularibus, plus minusve con- 

 tortis, irregularitates superficies hospitis arete adhaerantibus, mono- 

 stromatica aut pro parte distromatica composita; filamentis erectis 

 300-700/x longis, simplicibus aut superne ramis panels, brevibus, 

 plerumque secnndis, fructiferis indutis; cellulis filamentorum erec- 

 torum basim 6-8/t diam., 2-3-plo longioribus, apice ll-13ju, diam., 

 1-1.5-plo longioribus, cellulis multis in parte superiore filamentorum 

 1-2-plo longitudinaliter divisis; chromatophoris taeniatis. in eellula 

 quaque paueis; zoosporangiis numerosissimis, forma magnitudineque 

 maxime variabilibus, anguste ellipsoideis, clavatis, usque ad late 

 ovoideis, 40-130/a longis, 20-35/* latis, sessilibus aut pedicellis brevibus 



