19-5] Setchett-Gardner: Melanophyceae 389 



The classification of the Melanophyceae is in a very unsatisfactory 

 condition, that of Kjellman (1891) and that of Oltmanns (1904) 

 seeming very imperfect, especially since the later studies of Sauvageau, 

 Kylin, and others have changed our views in so many important 

 respects. The more recent classifications of Kylin (1917), of Oltmanns 

 (1922) and of William Randolph Taylor (1922) have assisted greatly 

 toward a more natural arrangement. We have therefore adopted many 

 of the views of Kylin (1917) and of Oltmanns (1922) and have incor- 

 porated some additional ideas of our own. Oltmanns has divided the 

 subclass into seven orders. In this, we are inclined to follow him, but 

 think it better to regard some of the other divisions also as of equal 

 rank with these. According to our scheme, the Melanophyceae of the 

 Pacific Coast of North America are arranged in the following manner : 



Key to the Series 



1. Reproduction sexual only 3. Cyclosporeae (p. 662) 



1. Reproduction both sexual and non-sexual 2 



2. Aplanospores present 2. Aplanosporeae (p. 649) 



2. Aplanospores absent 1. Phaeosporeae (p. 389) 



Series 1. PHAEOSPOREAE thuret 



Thallus composed of simple or branching filaments either of a 

 single row of cells (monosiphonous) or solid with diverse tissues or of 

 simple or solid membranes, or cushion form, branched or unbranched, 

 sometimes hollow, variously aggregated; non-sexual reproduction 

 (where known) by zoospores with 2 lateral cilia produced in unilo- 

 cular zoosporangia ; aplanospores never present ; gametangia pluri- 

 locular. or in one order (Laminariales) unilocular, male gametes 

 motile, biciliated, female gametes motile and biciliated or non-motile; 

 gametophyte and sporophyte similar or more or less dissimilar. 



Phaeosporeae Thuret, Rech. sur les zoosp. I, 1850, p. 233 (p. 24. 

 repr.) ; Kjellman, in Engler and Prantl, Xatiirl. Pflanzenfam., Teil 1. 

 Abt. 2 (Lief. 60), 1891, p. 180 (in part) ; Oltmanns, Morph. und Biol, 

 der Algen, vol. 1, 1904, p. 348. Phaeozoosporeae De-Toni, Syst. 

 Uebers. Fueoid., 1891, p. 175. Phaeosporales Oltmanns, Joe. cit., p. 348. 



The Phaeosporeae of Thuret have generally been regarded as con- 

 stituting an order, but they seem to us rather to represent a series 

 under the subclass Melanophyceae composed of the orders Sphace- 

 lariales, Ectocarpales, Cutleriales, Dictyosiphonales, Desmarestiales, 

 and possibly also the Laminariales. The general characteristic is the 

 occurrence of the typical brown zoospores of the Melanophyceae. These 

 are, as yet, unknown in some genera and species of the series, while 



