304 University of California Puhlications in Botany [Vol. 8 



3. Gomontia habrorhiza S. and G. 



Plate 19, figs. 2, 3 



Filaments repeatedly and irregularly branched ; cells very variable 

 in form and size, typically cylindrical, 4-7/x diam., 2-8 times as long; 

 chromatophore without pyrenoids, filling the cell ; ' ' sporangia ' ' nar- 

 row to wide, bluntly conical, 50-70/i, high, 25-60/* wide, developing 

 many very slender, attenuate, dendritically branched rhizoids from 

 the lower side ; reproduction unknown. 



Growing in dead clam shells. Neah Bay, Washington. 



Setchell and Gardner, Phyc. Cont. I, 1920, p. 299, pi. 24, figs. 2, 3. 



In certain shells from Neah Bay we have found all the ''sporan- 

 gia" of the Acarid-type and with the processes or rhizoids slender, 

 branched, and attenuated to a point. The "sporangia" seem so 

 distinct from those of G. Bornetii that we described the plant possess- 

 ing them as new. In some shells, we have found the "sporangia" of 

 this species intermingled with others. The vegetative filaments of 

 G. habrorhiza seem less entangled and slightly larger than those of 

 either G. polyrhiza or G. Bornetii. 



4. Gomontia caudata S. and G. 



Plate 18, figs. 1, 2 



Filaments short, sparsely branched; cells 5.5-6.5/* diam., 2-12 

 times as long; chromatophore covering the terminal cells and j'oung 

 "sporangia," broken in the older cells; pyrenoids inconspicuous; 

 "sporangia" clavate, 50-70/1 diam., 160-200/i long, tapering to a single 

 rhizoid below with thick, hyaline, homogeneous wall at maturity; 

 rhizoid often becoming much thickened and striated. 



Growing in shells of Mytilus calif ornicus. Neah Bay, Washington. 



Setchell and Gardner, Phyc. Cont., 1920, p. 300, pi. 23, figs. 1, 2. 



We have found in shells of the larger edible mussel of our coast 

 a Gomontia with filaments seemingly less abundantly branched and 

 "sporangia" (aplanosporangia?) with very thick walls and with a 

 single long rhizoid (cf. pi. 18, figs. 1, 2). These "sporangia" bear a 

 certain resemblance to the "cells" figured by Lagerheim (1885, pi. 28, 

 fig. 4, 6) but are, at least, thicker walled. The fact which seemed to 

 indicate distinctness was that only this type of "sporangium" was 

 found in the shells examined. 



