1925] SetcheU-Gardner: Mclanophyceae 571 



FAMILY 16. CHORDARIACEAE reichexh. (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 familj^ 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. 



