Ulothrix 155 



The species seems to be less abundant than U. flacca, but it is 

 probable that in some cases it has been confused with the latter or 

 with fresh water forms. 



Professor Wille (*Oi) has apparently described under the new 

 name if. subflaccida the form which has long been identified as U. 

 implexa. His reasons for rejecting, or at least holding in abeyance, 

 Kiitzing's name (chiefly on the ground that it cannot be determined 

 from literature just what Kiitzing's species was) seem to be insuffi- 

 cient. Many current names cannot be vouched for with absolute 

 certainty, but until their modern application is proved to be incor- 

 rect it is less confusing to retain them. One point emphasized by 

 Professor Wille is that the habitat of U. implexa as given in the 

 Tabulae Phycologicae is "in Graben " ; but he seems to have over- 

 looked the original description (Bot. Zeitung, 1 847) where it is stated 

 that the species is found " in submarinis, inter Rhizoclonium inter- 

 ruptum" — exactly the sort of habitat where we find our U. implexa. 

 The illustration in Tabulae Phycologicae is not bad for our species, 

 when it is remembered that it was made (probably) from dried ma- 

 terial. 



8. Ulothrix flacca (Dillw.) Thuret ; Le Jolis, Mem. Soc. Imp. 



Sci. Nat. Cherb. 10 : — (56). 1864. Farlow, Mar. Alg. 45. 



1 88 1. Reinbold, Schrift. Nat. Ver. Schles. -Hoist. 8 : 129. 



1889. Foslie, Tromso Mus. Aarsh. 13: 144.//. j.f. 1-3. 



1890. 



Conferva flacca Dillwyn, Brit. Conferv. //. 49. 1805. Eng. 

 Bot. pi. 194.3. 1808. Lyngb. Tent. Hyd. Dan. 144. pi. 49 A. 

 18 19. Aresch. Phyc. Scand. Mar. 205. 1850. 



Lyngbya CarmicJiaelii Harv.; Hook. Brit. Flor. 2 1 : 371. 

 1833 ; Phyc. Brit. 4: pi. 186 A. 185 I. 



Hormidium flaccum Kiitz. Phyc. Gen. 244. 1843. 



Hormotrichum flaccum Kiitz. Spec. Alg. 381. 1849; Tab. 

 Phyc. 3: //. 63. 1853. 



Lyngbya flacca Harv. Phyc. Brit. 1 : xxxviii ; 4 : pi. 300. 

 1851. 



Hormiscia flacca Aresch. Alg. Scand. 34.2. 



Urospora penicilliformis Aresch. Act. Reg. Soc. Sci. Upsal. III. 

 9 1 : No. 1. p. 4. p.p. 1874. DeToni, Syll. Alg. 1: 232. il 



