158 Ulothricaceae 



Exsic: Tild. Am. Alg. ijo. Yellowstone Park, 1896. 



These two varieties are forms of similar character, both grow- 

 ing in warm water, and it is very probable that they should be 

 united into one species. 



The diameter of Ulothrix thcrmarum is 5-6/7., with cells 1-3 

 times as long. Gloeotila caldaria has a diameter of 5 11 (Kiitzing) 

 (5.6-7.5 ft, Rabenh.) with cells 2-3 times as long. 



Without study of fresh material it is impossible to say whether 

 these forms belong to Ulothrix or to Stichococcus. 



II. STICHOCOCCUS Nageli, Neue Denkschr. Allgem. Schweiz. 



Gesell. io 7 : 76, yy. 1849. Gay, Rech. sur Alg. Vert. 



77-79. 1 89 1. 



Ulothrix {Hormidium) Kiitz. Spec. Alg. 349. /. p. 1849. 

 Not Hormidium Kiitz. Phyc. gener. 244. 1843. 



Hormococcus Chodat, Beitr. Krypt. Flor. Schweiz, I 3 : 268- 

 270. 1902.* 



Filaments without a special basal cell, fine, consisting of few 

 cells or long and Ulothrix-like ; chromatophore a parietal curved 

 disk or plate, usually covering not more than half of the cell-wall, 

 containing one pyrenoid, the nucleus usually on the opposite side 

 of the cell. 



Vegetative reproduction by dissociation of the filament into 

 single cells. Asexual reproduction through bi-ciliate zoospores 

 without eyespot, which are formed singly in any cell, escape 

 through a small round hole in the cell-wall, and germinate with- 

 out formation of a holdfast. 



Inhabitants of damp earth, or rock, or fresh water, one species 

 in brackish or salt water. Type 5. bacillaris Nag. [Etym. 

 OTiyo<z y row, series, and xoxxo^, berry.] 



The genus Hormidium as first named by Kiitzing in Linnaea, 

 17 : 89. 1843, contained three species, H moniliformc, H veluti- 

 num } H flaccum (Dillw.), of which the first two were nomina niida. 

 His Phycologia generalis, published later in the same year, in- 



* The action of Chodat in proposing this new name is inexplicable. All the species 

 included in it are placed by recent authors in Stichococcus, and the two genera are 

 therefore exactly synonymous except that for the type of this new genus the species 

 Stichococcus flaccidus has been selected instead of S. bacillaris. Equally unjustifiable 

 in the light of recent investigation is the inclusion of the well-marked species S. flac- 

 cidus, S. disiectus, S. bacillaris and S. fragilis to say nothing of Hormidium nitens, as 

 varietal forms under the single Sammelspecies Hormococcus flaccidus. 



