140 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.3 



The following species of the subgenus EURHODYMENIA are un- 

 certain of placement because of sterile material or inadequate descriptions 

 of the types. 



(32) RHODYMENIA PALMETTIFORMIS sp. nov. 



Plate 22, Fig. 29 



Frons 4-10 cm. alta, e disco simplici pauca, valde stipitata, stipitibus aliquando 

 paulum super discum ramiferis aliquando stoloniferis ; laminis variabilibus, e 

 stipite supero complanata gradatim expansis, dichotomis, interdum in segmentis 

 ultimis angustis, sed vulgo in apicibus late-lobatis 1.5-3 cm. latis expansis, fre- 

 quenter paululum palmatis, 100-150 \x crassis. Tetrasporangiis cystocarpiisque 

 nondum visis. 



Fronds 4-10 cm. high, several from a simple, discoid holdfast, prom- 

 inently stipitate; stipe sometimes branching just above holdfast, some- 

 times stoloniferous ; blades variable, expanding gradually from the flat- 

 tened upper stipe into dichotomies, sometimes ending in narrow ultimate 

 segments but commonly tending to expand into a broad-lobed apex, 1.5-3 

 cm. across, often somewhat palmate, 100-150 jj, thick. Tetraspores and 

 cj^stocarps unknown. 



Type. — ^Washed ashore. La Jolla, San Diego Co., Calif., Mrs. E. 

 Snyder No. 692 in Collins, Holden, and Setchell, Phycotheca Boreali- 

 Americana (1900) Fasc. XIV, sub. R. corallina (Bory) Grev. (from 

 set in Herb. W. A. Setchell). 



Cast ashore, Carmel Bay, Monterey Co., Calif., W. A. Setchell 1572, 

 Dec. 31, 1896. 



There is some overlapping of R. palmettiformis and J^. californica 

 with respect to the external morphology of the stipe; this may be some- 

 what shorter in the former and longer in the latter, causing confusion in 

 the distinction. The frequently expanded terminal segments seem, how- 

 ever, to be a feature of R. palmettiformis alone. 



Like Rhodymenia palmetta, R. palmettiformis is a conspicuously stip- 

 itate species in which the stipe may even superficially resemble that of 

 some members of Sec. Dendrymeniae. However, upon comparison of 

 many forms of Dendry/nenia with those of the other subgenus, Eurhody- 

 menia, it is seen that the branching may occur in the latter a short dis- 

 tance up from the holdfast, on account of the development of potential 

 blade-producing stolons at that point. In Mrs. Snyder's specimen men- 

 tioned above there is a distinct branching of the stipe just above the hold- 

 fast, indicating that branching is stoloniferous rather than truly sym- 

 podial. In one collection from San Pedro, California specimens which 



