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287
resemble conceptacles in form and origin». This statement stands
for Rokr, for the authors she has quoted (SmiTH and WHITTING in
Phycol. Memoirs I) only say that »a section across the leaf forcibly
recalls the conceplacles of Splachnidium and other brown algae». It
need hardly be said that Roe’s statement is quite without founda-
tion, as the sori of Macrocyslis or Postelsia have nothing in com-
mon, neilher in structure nor in origin, wilh the conceptacle of
Fucus. But Roe concludes that in this feature as well as in the
contents of the reproductive sacs, Splachnidium is intermediate
between the two orders mentioned; we do not know indeed, what
these sacs conlain — most likely zoospores, homologous both with
the spores of Laminaria and with the sexual bodies of Fucus; if
they are gametes, as in the Phaeosporeae, they are not homologous
with either. »Further investigation will doubtless show a much
more inlimate connection between the Laminariaceae and the Fuca-
ceae than is at present recognized», Ror continues, but I very
much doubt that this prophecy will ever be fulfilled. It may be
placed with either group, only, the presence of conceplacles »makes
it wise to regard Splachnidium as a primitive member of the Fuca-
ceae». In my opinion it is extremely different from both. I have
looked for natural affinities among the Chordariaceae; the structure
is not essentially distinct from Chordaria, Lealhesia etc.; the mulli-
cellular assimilators are represented by the hairs of the growth
zone, but they are a juvenile feature in Splachnidium. The spor-
angia have the same origin and the same appearance in both cases,
they are located in a sort of conceplacles, as the sexual organs in
Fucus, but the development of the conceplacle is not identical in
the two cases.
Splachnidium is quile a unique type; still I believe there are
reasons to regard it as represenling a branch of the Chordariaceae,
perhaps a »higher stage». I do not find sufficient grounds for
suppressing the order Splachnidiaceae, which, from a taxonomic
point of view, is well circumscribed. There is no evidence that
Splachnidium is intermediate between the Chordariaceae and any
other order.
July, 1920,
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