146 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



phology of this species is so outstanding that it need not be confused with 

 any other members of the Rhodymenia assemblage. 



As shown in Plate 21, the sympodial method of growth is essentially 

 the same in R. Skottsbergii, R. flabellifolia, and R. corallina, indicating 

 close relationships among these South American species. This character 

 is not so easily identified in other members of Sec. Dendrymeniae, but 

 may prove to be similarly present as more and better material is available. 

 Rather than to segregate all of these typically rhodymenioid species into 

 another genus (Dendrymenia), it has seemed best to keep them within 

 Rhodymenia but to give them separate section status. 



(40) RHODYMENIA RHIZOIDES sp. nov. 



Plate 20, Fig. 16 ; Plate 26, Fig. 37 



Frons 12-15 cm. alta, pauca e disco primario per stolones laxe impHcatas basi 

 stipitis prolificantes obscurando; stolonibus copiose raraosis, superne compressis, 

 aliquando proliferentibus; lamines late flabellatis, e basi late cuneatis, segmentis 

 4-5 mm. latis, apicibus rotundatis (iis in spec. typ. plus minusve laceratis prolif- 

 icantibusque) plus minusve 140 \i crassis, cellulis medullaribus 2-3 stratosis, 

 magnis ad cellulares parvas corticales gradatim parvioribus; tetrasporangiis cysto- 

 carpiisque nondum visis. 



Fronds 12-15 cm. high, several from a primary discoid holdfast ob- 

 scured by the loose tangle of branched stolons proliferating from the 

 lower parts of the stipes, these creeping and frequently giving rise to 

 erect branches which develop blades; stipes abundantly branched, com- 

 pressed above, sometimes somewhat proliferous ; blades broadly flabellate, 

 broadly cuneate from the stipe; segm.ents 4-6 mm. wide, with rounded 

 apices (these somewhat lacerated and slightly proliferous in the type) 

 about 140 [X thick, composed of 2-3 layers of large medullary cells showing 

 gradation in size from the small cells of the cortical region; tetraspores 

 and cystocarps unknown. 



Type.—?>zn Diego, Calif., June 1924, N. L. Gardner; Herb. Univ. 

 Calif. 377902. 



(41 ) RHODYMENIA HANCOCKII sp. nov. 



Plate 20, Fig. 20; Plate 26, Fig. 38 



Frons partibus basalibus intimis ignota, ramosa, teres, stipitibus abrupte in 

 laminas stricte regulariter dichotomas, flabellate expansis, segmentis inferis fere 

 angulis rectis patentibus; segmentis 4.5-7 mm. latis, apicibus rotundatis, 150-400 \i 

 crassis, interne pluristratosis, cellulis gradatim e centre ad superficiem parvioribus. 

 Tetrasporangiis cystocarpiisque nondum visis. 



