174 Ulothricaceae 



Filaments forming bright green or yellowish -green floccose 

 masses or long skeins ; cells usually cylindrical, rarely slightly 

 constricted at the joints, 14-17// (generally 16.5, rarely 18//) in 

 diameter, 1-2 j£ times as long; cell-wall rather thin; chromat- 

 ophore pale green, often perforated or reduced to a reticulum ; 

 zoospores rare; akinetes 18-22// (mostly 19.5 //) in diameter, 

 spheroidal, cuboidal, or almost cylindrical in shape {pi. 24.,/. 1-4). 



Exsic: Phyc. Bor. Am. 864. p.p., Pine Banks Park, Melrose, 

 Mass., May 15, 1901, F. S. Collins. 



Floating in streams and stagnant waters. One of the most 

 abundant of simple confervae. 



Massachusetts: Melrose, April (553); Framingham, May. 



New York : Van Cortlandt Park, April to June (349B, 599, 

 286, 634) ; Bronx Park, June (605, 626). 



New Jersey: Grantwood, March to May (437, 529, 283); 

 Edgewater, March (66A) ; Weehawken, May (409). 



This species, i. e., the name Microspora floccosa, has received 

 two divergent and apparently fncompatible interpretations as indi- 

 cated in the list of synonyms. By Kiitzing, Rabenhorst, Kirchner, 

 Wille, and Hansgirg, it has been described as having a diameter of 

 7.5-10//. By Cooke, Wolle, and De Wildeman, the diameter is 

 increased to 14-17 or 18//. DeToni combines the two concep- 

 tions, making the diameter 10-18//. How this difference arose, it 

 is impossible to say. 



To determine just what the original form, Prolifcra floccosa 

 Vauch.,was, is an equally difficult matter. Probably few students 

 of our time would venture to take the confident attitude assumed 

 by Agardh in relation to the identity of his Conferva floccosa and 

 Vaucher's species.* 



As a matter of fact such a barren figure and meager descrip- 

 tion as those of Vaucher are about equally applicable to any spe- 

 cies of Microspora or to most of the members of this family. For 

 further light on Agardh's conception of the species almost the 

 only point of value is his reference to Conferva fngacissima Lyngb. 

 as a synonym. Lyngbye's figure evidently represents a Microspora ; 

 it is the earliest illustration of the characteristic chromatophore 

 structure. It is doubtful if this structure could have been so well 



* Agardh remarks (Alg. Dec. 19. 1812), "Species nostra certe Prolifera floc- 

 cosa Vauch. esse videtur. Convenit enim et descriptio et pulchra icon." 



