550 University of California Publications in Botany [Vol. 8 



30. Heterochordaria S. and G. 



Main fronds cylindrical, at first solid, later becoming hollow and at 

 times slightly swollen, not forked but densely clothed on all sides with 

 longer or shorter, subcylindrical or slightly flattened, ramuli. few to 

 many arising from a thin prostrate, profusely branched or lobed. 

 parenchymatous thallus firmly adhering to rocks; interior of fronds 

 composed of thick-walled, colorless, parenchymatous cells surrounded 

 by small color bearing surface cells in anticlinal rows; zoosporangia 

 situated among numerous paraphyses and scattered hairs ; gametangia 

 arising through the transformation of approximately the lower two- 

 thirds of the cortical filaments. 



Setchell and Gardner, Phyc. Cont., VII, 1924, p. 6. 

 The finding of both zoosporangia and gametangia on macroscopic 

 plants of Chordaria abietina Rupr., and the finding only of zoo- 

 sporangia on the well known Chordaria jiageUiformis (Muell.) Ag. 

 indicates the extremely strong probability of a fundamental difference 

 between C. abietina and C. fiagelliformis as to the character of the 

 gametophyte. In view of our present attitude as to the bearing of 

 such a difference on the taxonomic position of the two plants, it seems 

 desirable to make C. abietina the type of a new genus and a new family 

 of the Ectocarpales and to place C. flagelliformis and its allies of the 

 Chordariaceae (in restricted sense) in another order, the Chordariales 

 and near to the Dictyosiphonales to which they (the Chordariaceae as 

 we restrict them) seem fairly closely related. 



There may be associated with this family, another genus, or even 

 two, viz., Ruprechtiella Yendo (Trav. Mus. Bot. de l'Acad. Imp. Sci. 

 St. Petersb., vol. 10, 1913, p. 117) which may be the same as Analipus 

 Kjellm., and the Chordaria Gunjii Yendo (Nyt. Mag. Naturvidensk., 

 vol. 51, 1913, p. 280) which may simply be the gametangial form of 

 some species of Myelophycus. 



Heterochordaria abietina (Rupr.) S. and G. 



Plate 36, figs. 18, 19, and plate 91 

 Erect fronds, 10-30 cm. high, flaccid, gregarious, many arising 

 from a single, widespreading, profusely branched, parenchymatous 

 horizontal thallus ; main axis slightly compressed above, terete below, 

 thickly beset on all sides with radiating ramuli 1-5 cm. long, tapering 

 at both ends, cylindrical to narrowly linear, both main axis and ramuli 



