1922] Setchell-Gardner : Phycological Contributions 353 



III. NEW SPECIES OF COMPSONEMA 



Introduction 



The genus Compsonema was established by Kuekuck. We have 

 accepted the genus to include forms which, like Myrionema, start 

 from a single cell that, by divisions, soon originates a series of closely 

 crowded, radiating filaments, forming a monostromatic basal layer 

 more or less circular in outline ; and which, unlike Myrionema, produce 

 on erect filaments numerous gametangia that develop pluriseriate 

 loculi. The genus is very closely related to the genus Myrionema on 

 one side and to Hecatonema on the other. No species of this genus 

 have previously been reported from the Pacific Coast of North America. 



Compsonema streblonematoides sp. nov. 



Plate 35, figure 4 



Frondibus pulvinulos tenues, orbiculares, 3-5 mm. diam. for- 

 mantibus; parte prostrata filamentis irregularitates hospitis arete 

 adhaerantibus composita, inferne ramulos radiciformes inter cellulas 

 hospitis usque ad 300-350/* profunditate penetrantes, superne filamenta 

 sterilia gametangiaque emittente; filamentis erectis 140-160/x longis; 

 cellulis filamentorum erectorum cylindricis, 8.5-10;a diam.. 1.5-3-plo 

 longioribus; zoosporangiis ignotis; gametangiis plerumque cylindricis, 

 brevi-pedicellatis, 55-70/* longis, ll-ll/t latis; loculis plerumque 

 2-seriatis. 



Growing on the pneumatocysts of Nereocystis Luetkeana. IMouth 

 of Tomales Bay, Marin County, California. Type, Gardner, no. 3442a 

 (Herb. Univ. Calif., no. 207035), August. 



Compsonema strehlonematoides, like a Strehlonema, has a large 

 part of the vegetative portion of the frond within the host-plant, the 

 penetrating filaments extending into the host two to three times as far 

 as the length of the external vegetative filaments. The whole frond, 

 however, is the result of the growth of a single cell and forms a compact 

 monostromatic basal disk. In the character of the gametangia it is 

 close to a Myrionema, but in a very large majority of cases the loculi 

 are biseriate. i 



