1920] Setchcll-Gardner: Chlorophyceue 189 



zoospores or gametes as the case may be. There seems also to be a 

 very considerable multiplication of pyrenoids at about the same time. 

 In the following account we have described the ciiromatophores as 

 well as the material allows, pending investigation of living plants. 



The filaments of Hormiscia are attached at the ba.se, at least at 

 first. The}' are usuall}' attached to rock or wood, but may be, in some 

 species at least, attached to other algae. Kjellman (1897, p. 8 et seq.) 

 was the first to call attention to the variety in tlie method of attach- 

 ment of the filaments of Hormiscia, contrasting tiiose of H. penicilli- 

 formis with those of H. incrassata. The differences depend upon the 

 behavior of the rhizoidal outgrowths from the basal segments. In 

 some species only a few of the lower segments emit rhizoids, while in 

 others twenty or more of the basal segments may produce them. In 

 some species the rhizoids do not emerge from the outermost walls of 

 the filament but descend along the segments below them, still enclosed 

 within the walls, until the very base or near it, when they may or may 

 not emerge and become free. We have designated such rhizoids as 

 intram-atrical. In some species, however, tlie rhizoids do not descend 

 for any considerable distance within the outer wall of the filament, 

 but emerge at once and cither extend at any angle to the filament or 

 descend closely applied to it. Such rhizoids are designated by as as 

 extramatrical. (For tlie terms intramatrical and extramatrical see 

 Jonsson, 1903, p. 360.) 



In diameter the filaments vary considerably, both in regard to 

 the different species and in regard to the segments in different por- 

 tions of the same filament as well as in filaments of different ages. 

 The filaments taper from tlie base upwards and then often narrow 

 again more or less towards the apex. The tapering upwards is slight 

 in some species l)ut more considerable in others. In most species it 

 is gradual but in other species it is abrupt. The diameters of the 

 reproductive segments are usually the most distinctive. 



The shape and proportions of the segments, especiall}^ of the fertile 

 segments, vary considerably among the species, but are sufficiently 

 constant to furnish valuable characters for diagnoses. The thickness 

 and structure of the wall, ])artieularly of the reproductive segments, 

 offers additional points of difference between species. The consistency 

 of the plants, as observed in mass, varj'ing fi-oni lubricous to fleecy, 

 is worthy of attenliou, wlutlier judged from observation of the living 

 specimens or from the extent to which they adhere to paper in drying. 



In attempting to arrange the |)laiits of our coast, it has been 



