1922] Setchell-Gardner : Phycological Contributions 377 



IV. NEW SPECIES OF HECATONEMA 



Introduction 



The genus Hecatonema was established by Sauvagean (1897, 

 p. 249). We have in the Herbarium of the University of California 

 numerous collections of small epiphytic plants found upon Nereocystis 

 Luetkea^ia in various localities on the Pacific Coast, which we have 

 placed in the genus Hecatonema. This genus, as we interpret it, is 

 quite similar to Compsonema and to Myrionema, but differs from each 

 in having a distromatic base. Of the two, it seems more nearly akin 

 to Compsonema than to Myrionema in that it develops gametangia 

 with pluriseriate loeuli instead of uniseriate, as is the ease in Myrio- 

 nema. 



There have been no species of this genus reported previously on the 

 Pacific Coast of North America. This study is but a preliminary one 

 and it is hoped that it may stimulate further investigation of this genus 

 as well as of the other closely related genera. 



Hecatonema variabile sp. nov. 



Plate 41, figures 1-12 



Frondibus pulvinulos orbiculares, 4-7 mm. diam. formantibus ; 

 parte prostrata filamentis radiantibus subapicaliter ramosis, per 

 ramulos radiciformes numeros, breves, 1-3-cellulates adhaerantibus 

 composita ; filamentis erectis non dense stipatis. non e centro ad peri- 

 pheriam seriater evolvatis, simplicibus. 400-500/* longis; pilis veris 

 ignotis; cellulis filamentorum repentium forma irregularibus. 7-9/4 

 diam., margine 1-3-plo longioribus ; cellulis filamentorum ereetorum 

 basim 4.5-5/a diam., 2-5-plo longioribus, apice S-lOju, diam., 1-3-plo 

 longioribus; zoosporangiis( ?) late clavatis in filamentLs prostratis 

 sessilibus brevi-pedicellatisve raro in filamentis erectis terminalibus 

 lateralibusve, 50-65/i, longis, 20-24/i latis; gamentangiis cylindricis, 

 apice leviter attenuatis. in filamentis sessilibus brevi-pedicellatisve, 

 raro in filamentis erectis terminalibus, 70-120/x longis, 9-12/* latis; 

 loeuli 1-2-seriatis. 



Growing on the pneumatocysts of Nereocystis Luetkcana. Carmel 

 Bay, Monterey County, California. Type, Gardner, no. 3109 (Herb. 

 Univ. Calif., no. 207050), December. 



From the standpoint of the structure of the gametangia, the type 

 of this species of Hecatonema could scarcely be separated from a 



