358 UniversHy of California Puhlications in Botany [Vol. 7 



filninciitis reii('i)til)us oriniulis siifTiiHls. ant in filMmeiitis erectis 

 lalcralihus tcniiiiialihiisvc ; f^ainctaiiffiis raris, cylindricis, in filamentis 

 reiiciitihus scssilihus hn'vi-ix'diccllatisve ant raro in filamentis erectis 

 Irniiin.ilihus Inhereulatisqne, 8()-]30/a longis, 11-15/i, latis. 



(Jrowinj,'- on tiie i)neuiiiatuey.st of Nereocystis Luetkeana. Neah 

 Bay, Washington. Type, Gardner, no. 3859 (Herb. Univ. Calif., no. 

 207038). :\ray. 



Tlie unusual condition in Compsonema prevails in C. sporangii- 

 fcnun. The gametangia seem to be of rare occurrence. Examination 

 of specimens of different sizes from different parts of the host revealed 

 the presence of a large number of zoosporangia in all stages of develop- 

 ment, man>' I)eing empty. The gametangia are prevailingly near tlie 

 base, although occasionally a complex one appears terminal on an erect 

 lilaiiii'ut. A very common character is the division of the cells in the 

 u|)|)ci' i)arts of the filaments into 2-4 parts by longitudinal walls, pro- 

 ducing a slight clavate condition in such filaments. AVe do not know, 

 at present, tlie morphological significance of this condition. The 

 zoosporangia and the gametangia, so far as observed, develop on distinct 

 individuals. 



Compsonema sessile sp. nov. 



Plate 39, figure 6 



Frondibus pulvinulos inconspicuos usque ad 1.5 mm. diam., in linea 

 exteriore orbiculares usque ad irregulares formantibus; filamentis 

 repentibus contortis, dense compactis, hospitem arete adhaerantibus, 

 ramulis radiciformibus deuntibus; filamentis erectis sparsis 20-2-!:,u 

 altis; pilis veris deuntibus: collulis filamentorum repentium foimia 

 magnitudineque irregularibus, 9-12/x diam.; chromatophoris taeniatis 

 in cellula quaque singulis; zoosporangiis ignotis; gametangiis numer- 

 osis, in filamentis repentibus sessilibus, conicis usque ad fusiformibus, 

 16-22/i longis. ll-14ju, latis, parietibus multorum loculorum obliquis. 



Growing on the lamina of HedophyUum sessile near the outer end. 

 Neah liay, Washington. Type, Gardner, no. 3866 (Herb. Univ. Calif., 

 no. 207039), May. 



Compsonema sessile represents the extreme of the genus in the 

 direction of simplicity. There are no hair filaments, and it is doubtful 

 if any of the erect filaments remain sterile. At times even the cells of 

 the basal layer seem to become a part of the gametangia, at least more 

 than one cell in the basal layer may be at the base of a single game- 

 tangia. There would seem to be only a single modification of a 

 Myrianema of the simplest type to produce this species, viz., the 

 change in the type of gametangium from uniseriate to ])luriseriate. If 



