392 University of California Publications in Botany [Vol. 8 



some distance below the apical cell; branches variously arranged, 

 alternate and distichous or polystichous, or, at times, opposite and 

 distichous, occasionally distinguished into two sets, long (indefinite) 

 axes and short (definite) axes, but the latter never in regular whorls ; 

 otherwise as in the order ; propagula formed on certain species of 

 this family. 



Spliacelariaceae Reinke, Ber. d. deut. bot. Gesell., vol. 8, 1890, 

 p. 203 (in part) ; Oltmanns, Morph. und Biol, der Algen, vol. 2, 1922, 

 p. 85. 



On the west coast of North America are to be found few of the 

 Sphacelariales and none is frequent. The specimens which have been 

 found belong to the Sphacelariaceae. The Cladostephus verticillatus 

 (Liglitfoot) Ag., referred to the coasts of the Russian American 

 possessions on the North Pacific Ocean (Postels and Ruprecht, 1840, 

 p. 21) and apparently not in typical form, has not been seen since, so 

 that it does not seem best to continue to include it as belonging to our 

 flora. 



Key to the Genera of the Sphacelakiaceae 



1. Zoosporangia and gametangia borne on the regular branches from the axis 



1. Sphacelaria fp. 392) 



1. Zoosporangia and gametangia borne on special branches arising from the 



corticating filaments 2. Chaetopteris (p. 397) 



1. Sphacelaria Lyngb. 



Fronds forming relatively small, usually profusely branched, more 

 or less spherical or irregular tufts attached to the surface of rocks or 

 to other algae by small disk-like or thalloid holdfasts, or penetrating 

 into the substance of other plant bodies; the main axes and the 

 branches terminated by an apical growing cell which divides cross- 

 wise, the resultant segments sooner or later dividing lengthwise and 

 more or less obliquely, building up a polysiphonous frond, the sur- 

 face layer of which consists of transverse bands of rectangular cells 

 obscured below in corticating species; reproduction by unilocular 

 zoosporangia and by pluriloeular gametangia, and vegetative, by the 

 formation and separation of propagula, or bulblet-like portions of the 

 frond, produced on different individuals from the sporangia ; zoo- 

 sporangia and gametangia arising from the regular branches from the 

 axes of the plant, not from special branches produced from corticating 

 filaments. 



Lyngbye, Hydrophyt. Dan., 1819, p. 103. 



