F. Børgesen: List of species. 



431 



var. uvifera (Turner) J. Ag. 

 var. occidentalis (J. Ag.) Børgs. 

 var. lætevirens (Mont.) Web. v. Bosse, 

 var. Lamourouxii (Turner) Web. v. Bosse. 

 90. Vaucheria dichotoma (L.) Ag. 



Phæophyceæ. 



Pylaiella (Bory) Kjellmann. 

 Subgen. Bachelotia Bornet. 



1. Pylaiella fulvcscens (Schousb.) Bornet. 



Bornet, Ed., Note sur l'Ectocarpus (Pylaiella) fulvescens Thuret (Revue 

 generale bot., tome 1, 1889, p. 5, pi. 1); Les Algues de P.-K.-A. Schousboe 

 (Mémoires... Cherbourg, t. XXVIII, 1892, p. 247). Sauvageau, C, Note sur 

 l'Ectocarpus (Pylaiella) fulvescens Thuret (Journ. de Botanique, 1896, p. 47). 



Conferva fulvescens Schousboe mscr. ; Icon, ined., t. 116 in Herb. Thuret. 



Ectocarpus fulvcscens Thuret in Algæ Schousb. no's 109 — 110. 



This peculiar plant has been found 

 twice in two different collections inter- 

 mingled with other algæ. 



As is well known from Bornet's 

 and, more recently, from Sauvageau's 

 descriptions of this plant it has creeping 

 filaments fixed to the rocks by short 

 haptera; from these creeping filaments 

 the erect ones arise. In the material 

 gathered I have found small fragments 

 of the creeping filaments, but an 

 abundance of the erect filaments, these 

 having been cut over when collected. 

 In most of the erect filaments an inter- 

 calary growing zone was found in about 

 their middle. In this zone the cells are 

 dark coloured, the chromatophores fil- 

 ling up nearly the whole lumen of the 

 cells; these are all short being divided 

 as soon as they reach a length corre- 

 sponding to their breadth or even earher. 



Fig. 408. Pylaiella fulvescens 

 (Schousb.) Bornet. a, part of 

 a filament with rhizoids. b, 

 part of a filament with spor- 

 angia, a, about 150:1; b, 70:1.) 



