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1925] SetcheH-Gardner: Melanophyceae 571
family 16. CHORDARIACEAE reichenb. (in part)
Fronds erect, cylindrical, branched or simple, arising from discoid
holdfasts or from lobed and expanded horizontal thalli, composed of
three tissues or layers, an inner, of elongated, usually slender fila-
ments (often disappearing and leaving a hollow center), an inter-
mediate, of large, rounded, or somewhat elongated cells, and an outer
cortical layer, of short, anticlinal, assimilating filaments, distinct from
one another, but enclosed in an enveloping jelly ; zoosporangia
immersed among the cortical filaments ; gametangia and micro-
scopic (?) gametophyte unknown.
Reichenbach, Conspectus Regn. Veg., 1828, p. 25 (in part; fide
Pfeiffer, Nomen. Botan., vol. 1, 1873, p. 732, et auct. var.) ; Harvey,
Ner. Bor. Amer., I, 1852, p. 121 (in part). Chordarieae Agardh,
Syst. Alg., 1824, p. xxxvi (in part).
The family of the Chordariaceae, while actually very distinct from
all others of the Melanophyceae except that of the Heterochordariaceae
because of its subterminal growth and frond structure, has been the
recipient of several families in which the growth is clearly tricho-
thallic. We may assume with reason, we think, that -the subapical
method is intermediate between the apical and the trichothallic yet
distinct from each of them. The outer, cortical, layer of short, but
distinct, anticlinal filaments distinguish this family from both the
Coilodesmaceae and the Scytothamnaceae.
Key to the Genera
1. Fronds simple (in our species) or very sparingly branched 2
1. Fronds, typically, much branched 34. Chordaria (p. 571)
2. Fronds composed of a flattened, sterile part and an erect, fertile part
35. Analipus (p. 575)
2. Fronds not composed of two parts 36. Gobia (p. 576)
34. Chordaria Ag. (emend Grev.)
Fronds cylindrical, filiform, branched, more or less rigid and
cartilaginous to slightly lubricous, solid or at times becoming fistulous
in age, composed of two tissues, a medulla and a cortex ;
growth sub-
apical ; medulla composed of relatively large, colorless, longitudinally
arranged, firmly agglutinated filaments, with numerous small fila-
ments, especially abundant in the center of the frond, interspersed
cortical assimilating filaments short, firmly agglutinated ; reproduc-
tion in macroscopic plants by zoosporangia borne among the cortical
filaments.
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