NOTES ON THE BRITISH CHARACE;E FOR 1887-9. 67 



C. tenuissima vai\ batrachosperma, Babenh., Fl. Lusat. ii. p. 166 

 (fide Braun). 



C. tenuissima vars. batrachosperma & ramulosa, Gant. Oesterr. 

 Char. (1847), p. 10. 



N. tenuissima var. batrachosperma, Kuetz. Phyc. Germ. (1845), 

 p. 256; Eab. Deutsch. Krypt. Flor. (1847), p. 196. 



N. batrachosperma, Braun, Scliweiz. Char. (1847), p. 10, noraen 

 (non Agardh) ; Consp. Char. Europ. p. 2 ; Krypt. Flor. Schles. 

 p. 400 ; Fragmente Monog. Char. p. 66 t. 5, f. 131-2 ; Kuetz. Sp. 

 Alg. (1849), p. 515; Tab. Phyc. vii. (1857), t. 35, f. 1; Nordst. 

 Skand. Char, in Bot. Not. 1863, p. 36; Wahlst. Sver. & Norg. 

 Char. (1875), p. 20; Sydow, Europ. Char. (1882), p. 30 ; Migula 

 in Eab. Krypt. Flor. Deutsch. sect. 5 (1890), p. 184, f. 52-4. 



Exsiecata: — Areschoug, 150. Braun, B. & S. 78. Fries, Hb. 

 Norm. xvi. 100. Nordst. & Wahlst. 42. Eab. Alg. Sachs., 220:= 

 (fide Nordst.). 



Plant usually minute. Stem about -15-'2 mm. thick. Inter- 

 nodes from once to twice the length of the branchlets. Branchlets 

 usually 8 in a whorl, mostly twice divided, sometimes in the sterile 

 whorls only once divided, and rarely in the fertile whorls one of the 

 tertiary rays again divided. Bays of the first forking 4-5 ; 2-3 

 again divided into 3-5 rays, the remainder usually simple. Tertiary 

 rays usually about half the total length of the branchlets, 2-celled, 

 the ultimate cell •053--11 mm. long, -018--025 mm. thick at the 

 base, tapering to a sharp point. Fruit solitaiw, usually at the first 

 and rarely at the second forkings broadly ovoid, about *43 mm. 

 long, -29 mm. thick, coronula small. Oospore -23- -25 mm. long, 

 •21--22 mm. thick, slightly flattened when ripe, showing 7 striae, 

 side walls of the enveloping-cells becoming thickened, and re- 

 maining, when the outer wall has decayed, standing out as wing-like 

 ridges on the oospore. Antheridia at the same nodes as the fruit. 

 Monoecious. 



N. Nordstedtiana is one of the smallest species of the genus. It 

 is allied to A 7 , tenuissima, from which it may be distinguished by its 

 oospore having prominent wing-like ridges, and irregularly minutely 

 warty surface, which is shrivelled in appearance ; by its fruiting at 

 the first forking of the branchlets, which is very exceptional in N. 

 tenuissima; by the less rigid habit; by tbe more sharply-pointed 

 end-cells of the branchlets ; and usually by the proportionately 

 shorter internodes. 



The distribution of the species as recorded by Braun & Nord- 

 stedt is : — Finland, Sweden, Germany, France, Spain and Italy, 

 also North America (Massachusetts), and Australia. It was dis- 

 covered in Britain by Mr. W. S. Duncan, in July, 1888, in a loch 

 near Obbe, in the Isle of Harris, Outer Hebrides, and was forwarded 

 to us by Mr. Arthur Bennett. The British plant is a small form 

 from 1-2 inches high. Dr. Migula, in the recently-published edition 

 of Eabenhorst's Krypt. Flor. Deutsch., describes four forms under 



* The specimen in the British Museum is too bad to admit of identification 

 without soaking out, so we have followed Nordstedt in quoting it. 



F 2 



