355 — 



dl 



Qi 



which attain a thickness of G fj. Each ceH contains one lateral nucleus 

 and one chromatophore with a lateral pyrenoid. The chromatophore is 

 usually belt-shaped; it is considerably varying in breadth and sometimes 

 much broader on one side. The margin of the chromatophore is not 

 seldom somewhat lobed. The chromatophore not rarely seems to be a 

 curved, lateral plate with a lobed margin, and in such cases it superficially 

 resembles the chromatophore of Prasiola (cfr. also Wille I. c). Basal 

 rhizoids usually occur and consist of one or, more rarely, of three cells ; 

 they usually spring from the next cell above the basal cell. 1 have only 

 seen some few sporangia, some of which were of the same shape as tlie 

 sterile cells, other were 

 somewhat thicker and 

 of more rounded shape. 

 The number of zoo- 

 spores was, as far as 

 I could see in the dried 

 material, 6 — 10 in each 

 sporangium. The inner 

 layer of the membrane 

 next to the lumen of 

 the cell turns blue by 

 chlor-zinc-iodide , but 

 the outer layer of the 

 membrane turns red 

 by ruthenium oxychlo- 

 ratum ammonia, thus 

 the inner part of the 

 membrane consists of cellulose and the outer part of pectose. 



The plants I have referred to this species do not fully agree with 

 Wille's description. My specimens are somewhat thicker and their cells 

 somewhat lower, the number of zoospores is not the same, and regarding 

 the base and the articulated rhizoids they also seem to diflfer from the 

 Norwegian ))lants. 



Dried specimens of Bangia virescens Fosl. (Gontrib. I, p. 02, Tab. 2, 

 fig. 2—9), which I have seen here at the Botanical Museum, have a 

 great resemblance to my specimens. Bangia virescens Fosl. does not 

 belong to the genus Bangia but is undoubtedly to be regarded as a 

 Ghlorophycea, as the sterile cells are richly furnished with starch. The 

 chromatophores have, as far as I can see in the dried material, a shape 

 somewhat resembling that of my specimens described above, and each 

 cell contains one chromatophore with a single pyrenoid. The spores 

 mentioned and figured by Foslie (1. c.) are probably zoospores. Until 



c Da 



Fig. fi. Ulothrix consociata Wille var. islandica nov. 



var. f. geniculata nov. forma. a a base of a 



filament: b, <■., d fragments of kneed filaments, 



d showing three sporangia (215:1). 



