176 Ulothricaceae 



Exsic: Phyc. Bor. Am. 6/p, Melrose, Mass., March, 1894 



(F. S. Collins). 



Forming floccose masses in brooks and in stagnant waters. 



Massachusetts: Ipswich, May (558B). 



New York: Botanical Garden, May (376A, 407), June (609). 



New Jersey: Grantwood, April (530A); Edgewater, March 

 (66B). 



It is to be suspected that Scandinavian authors would include 

 under this name the form which we have determined as M. floccosa. 

 for in the vegetative condition there is the most perplexing simi- 

 larity between the two forms. Indeed we have found forms cor- 

 responding to M. floccosa, M. Willcana, and M. stagnomm all 

 mixed together, and forming what looked, at first sight, like a 

 graded series of growth forms. 



Nevertheless, in the fruiting condition, M. floccosa is easily dis- 

 tinguished from M. Willcana by its much larger akinetes, and it is 

 probable that by more exact and extended field study they could 

 be better distinguished when in the vegetative state. 



This problem did not present itself until too late for more 

 thorough field observations to be made in preparation for this 

 paper. 



7. Microspora stagnorum (Kiitz.) Lagerh. Ber. Deutsch. bot. 



Gesell. 5 : 417. 1887 ; Flora, 72 : 208. 1889. Hansgirg, Prod. 



Alg. Bohm. 2: 222. 1893. DeToni, Syll. Alg. 1: 229. 



1889. 



Conferva tenerrima stagnorum Kiitz. Alg. Dec. 56. 1833 ; 

 Flora, 16 : 700. 1833. 



Conferva stagnorum Kiitz. Phyc. Gener. 257. 1843. Wille, 

 Ofvers. Vet.-Akad. Forhand. 1881 8 : 20. pi. p.f 12-27. pi. I0 -f- 

 SO. 1881. Hansg. Prod. Alg. Bohm. 1 : 75. 1886. 



Glocotila stagnorum Kiitz. Phyc. German. 191. 1845. 



UlotJirix tenerrima stagnorum Kiitz. Spec. Alg. 346. 1849. 



Ulothrix stagnorum Kiitz. Tab. Phyc. 2 : 27. pi. 87. f 2. 

 1852. Rabenh. Krypt. Flor. Sachs. 1: 264. 1863; Flor. Eur. 

 Alg. 3: 366. 1868. 



Ulothrix tenerrima Rosenv. Bot. Tidssk. 1 1 : 121. pi. 1. f 

 1-14, 17-21. 1879. 



