ii66 Puget Sound Marine Sta. Pub. Vol. 1, No. 25 



12. HEDOPHYLLUM Setchell 



Holdfast composed of branched hapteres ; stipe at first short, later 

 disappearing; blade at first entire and regular, later becoming irregular 

 and much split up, thick, mucilaginous, its surface plane or very irregular ; 

 blade in older plants wearing away in the middle until it has the appearance 

 of several irregular blades which send out hapteres from their creeping 

 rhizome-like bases. 



The genus Hedophyllum as Setchell (14) has already pointed out, is 

 not entirely satisfactory. Good specimens in various stages of develop- 

 ment are needed for further study. 



KEY TO SPECIES 



A. ^Mature plant sessile ; blades several, crowded in a dense cluster. 



1. H. sessile 



AA. Mature plant apparently with short rhizome-like stipe ; blades several 

 united to each other by the rhizome-like stipe which is formed by the 

 base of the original blade. 2. H. suhsessile 



1. Hedophyllum sessile (Agardh) Setchell, Zoe 5: p. 122; (Laminaria 



sessilis Ag. Syst. Alg. p. 270). Fig. 20 



Holdfast composed of short closely crowded branched hapteres which 

 usually come from the base of the blade; stipe very short and flattened in 

 young plants but soon disappearing as the plants get older; blade at first 

 ovate and entire but soon becoming irregular and much split, sessile, bullate 

 cr rarely smooth ; mucilage ducts numerous and large. 



Forming dense beds near the low tide line on exposed shores. 



2. Hedophyllum subsessile (Aresch.) Setchell, Zoe 5: p. 123; {Lami- 



naria Bongardiana suhsessilis Aresch., Obs. Phyc. 4: p. 5.) Fig. 21 



Holdfast composed of branched hapteres ; stipe short, stout, somewhat 

 flattened, later disappearing; blade at first narrow and simple, then broader 

 and divided, finally with cordate base and marginal rows of bullate swell- 

 ings ; mucilage ducts large and frequent. In older plants the central por- 

 tion of the blade dies away to the base and forms two blades connected 

 by the margin of the old blade which sends out hapteres and forms a 

 rhizome-like holdfast. 



This species is not known to the writer from this region. Saunders 

 (13), p. 430, reports it as common in exposed places from Puget Sound 

 northward. The specimens referred to this species (8), p. 70, belong to a 

 much split form of Laminaria bullata. 



