198 Chaetophoraceae 



ib. Mvxonema lubricum varians var. nov. 



Tufts shorter, 5-15 mm. long ; filaments somewhat more slen- 

 der ; branches single or opposite, generally approximate on a 

 moniliform series of 3-10 shorter cells ; branchlets slender, needle- 

 shaped ; lower cells cylindrical or somewhat swollen, rather thin- 

 walled, 1 1 — 14 p. in diameter, 2—5 times as long [pi. 33, f. 4, 3; pi. 

 28, f. j, 4 ). 



On rocks and sticks, in rapid brooks and in watering-troughs. 



Massachusetts: Medford, in a clay pit, May 7, 1901 (F. S. 

 Collins, 3998). 



Connecticut: Norwich, May (559); Thomaston, May (542). 



New York : Central Park, May (384B), October (663); Flush- 

 ing, August (456); West Chester, May (388); New Dorp, Staten 

 Island, April, (334) ; Castleton Corners (330) ; Clove Lake (331) ; 

 Concord (336, type). 



New Jersey : Undercliff, May (432) ; Shadyside, April (304B). 



We have wavered between considering this form or collection 

 of forms a mere growth stage of M. lubricum and a distinct species. 

 The large number of specimens collected indicates that it is suffi- 

 ciently important to be recognized. It is generally easily distin- 

 guished from the typical forms'of M. lubricum by its smaller size 

 (both in diameter and length of the filaments) and the longer, thin- 

 walled cells. Though at times the branching is comparatively 

 simple, as a rule the tendency is to accumulate more extensive 

 series of branches than are commonly seen in M. lubricum. Where 

 the variety has been found with typical forms of the species, it has 

 seemed most distinct. In other cases the relationship has appeared 

 to be so close that it is thought best, at least tentatively, to con- 

 sider the smaller plant a variety of the larger. 



In respect to diameter this form is intermediate between 

 Myxonema tenue and M. lubricum, but in the matter of branching 

 it is usually rather more developed than either of these ; in some 

 cases it approaches M. amocnum. Much simpler forms are also 

 found, which must be associated with this variety. In our draw- 

 ings of Myxonema lubricum varians and M. tenue, the diameter of 

 the former has been represented as slightly smaller than it should 

 be and that of the latter is slightly too large, in comparison with 

 other species. 



