Myxonema 193 



On dead leaves in a rain-water ditch in the hemlock grove, 

 New York Botanical Garden, May, June (407, 608). 



The name given to this variety by Schmidle is hardly appro- 

 priate, as the cells are no longer than many in M. strictissimum. 

 The plant as here described agrees essentially with Schmidle's 

 diagnosis, though the branching is perhaps less strict. 



In the station above noted this form has appeared for a brief 

 period in May and June during two seasons. It is not present in 

 early spring, and the pool becomes dry upon the advent of warm 

 weather. 



II. MYXONEMA Fries, Syst. Orb. Veg. 343././. 1825; Flor. 



Scan. 329. 1835 



Stigcocloniinn Kiitzing, Linnaea, 17 : 90. 1 843 ; Phyc. Gen. 



253. i843- 



Thallus covered with a thin slippery investment of mucus, 

 consisting of a branched filament without great difference in re- 

 spect to diameter between the main stems and the minor branches. 

 Terminal branchlets pointed or frequently ending in long hyaline 

 setae. Chromatophore a parietal, often laciniate band, zonate in 

 the larger cells, nearly filling the smaller cells, inclosing several 

 pyrenoids. 



Asexual reproduction by means of 4-ciliate zoospores having a 

 red eye-spot, and akinetes which give rise to small 2-ciliate zoo- 

 spores, and through a palmella stage. 



Sexual reproduction through conjugation of 2-ciliate gametes 

 having a red eye-spot. Both gametes and zoospores formed only 

 in the vegetative cells of the branchlets. 



Inhabitants of fresh water. Type, M. lubricum (Dillw.) Fries. 

 [Etym. fJtuga, mucus, and v9jfjia, a filament.] 



The fact that the genus Myxonema, as proposed by Fries, was 

 composed of two diverse elements, probably accounts for its early 

 supersession by the more homogeneous genera of Kiitzing. The 

 first element comprised only the type (that is the first) species, 

 Conferva liibrica (syn. Drapamaldia Ag.), a well-known branched 

 form. The second element consisted of four unbranched 

 species, Conferva zonata (Web. and Mohr), C compacta Roth, C 

 oscillatorioides Agardh, and C dissiliens Dillwyn, of which three 

 are now recognized as species of Ulotlmx, and the last as a desmid. 



