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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