118 



BBITISH CHAEOPHYTA. 



Nitella gracilis Agaedh Syst. Alg. p. 125 (1824). 



CossoN & Gebmain Atl. Flor. Par. t. 41, f.E (1845) ; ed. 2, t. 47, f.F 



(1882). 

 KUTZING Phyc. Germ. p. 256 (1845) ; Sp. Alg. p. 515 (1849) ; Tab. 



Phyc. t. 34, f. 1 (1857) 

 Braun in N. - Denks. Soliweiz. Ges. Natui-w. X, p. 10 (1847) ; in 



Monatsb. Akad. Berl. for 1867, p. 885 (1868) ; in Oohn, Ki-ypt. Fl. 



Schles. I, p. 399 (1876). 

 Rabbnhorst Deutscb. Kiypt. PI. II, p. 194 (1847). 

 Wallman Porsok syst. Gbarao. p. 19 (1853) ; Transl. p. 17 (1856). 

 Wahlstedt Bidrag Skand. Charac. p. 1 (1862); Mon. Sver. & Norg. 



Cbarao. p. 19 (1875). 

 NoBDSTBDT in Bot. Notiser, 1863, p. 38 ; in Flora Danica, t. 2930, i 



(1877). 

 Crepin in Bull. Soc. Bot. Belg. II. p. 128 (1863). 

 Leonhaebi in Verb. Natui-f. ver. Brunn, p. 170 (1864). 

 Groves in Journ. Bot. XVIII, p. 164, t. 210, f. 15 (1880). 

 MiJLLER in Bull. Soc. Bot. Geneve II, p. 52 a881). 

 Beaxtn & NORDSTEDT Fragm. Mon. Cbarac. p. 58 (1882). 

 Sydow Europ. Cbarao. p. 25 (1882). 

 BoswELL Engl. Bot. ed. 3, XII, p. 183, t. 1903 (1884). 

 MiGTTLA Die Cbaraceen, p. 159, f . 45-^7 (1890) ; Syn. Charac. Europ. 



p. 39, f. 33-35 (1898). 

 GiESENHAGEN Unters. ii. d. Cbarac. I, p. 63, S. 29-36, 56 (1902). 

 HOLTZ Cbaraceen, in Krypt. Mark-Brandenb. p. 75 (1903). 

 Hy in Bull. Soc. Bot. France LX, Mem. 26, p. 14 (1913). 



ExsiccATA :— Arescboug, 50 (fide Wablstedt) ; Billot, 2992; Braun 

 Rabenb. & Stiz., 24, 25, 57-59 ; Desmazieres, 822 ; Fries, VII. 100 (fide 

 Sydow); Groves, 56; Lloyd, 423; Mougeot & Nessl. 1197; Migula, 

 Sydow & "Wablstedt, 51; Nielsen, 9 {fide "Wablstedt); Nordstedt & 

 "Wablst., 15-17; Eabenborst, 138,169,439; Reicbenbacb, 1.99; Scbultz, 

 IV. 91 ; Westendoi-p & "Wall, 1094. 



Monoecious. Stem yevj slendeY ; internodes as long 

 to t"wice as long as the branchlets. Whorls of 5-6 

 slender brancHets. Branchlets 2-3 times divided ; 

 primary rays about a half the total length ; secondary 

 rays 3-5 ; tertiary rays usually 3-4, of "which 1-2 are 

 again forked. Ultimate rays 2-3 celled, penultimate 

 cell somewhat tapering upwards, usually not more, and 

 often considerably less, than twice as thick at the apex 

 as the base of the long narrowly-conical acute ulti- 

 mate cell. Third cell when present much longer than 

 the penultimate cell. Furcations often all fertile, an 

 oogonium or antheridium or both being present. 

 Oogonia solitary, at first subglobose, becoming ovoid- 

 conical through the lengthening of the spiral cells at 

 the apex, c. 525 /a long, 850 /a broad; spiral cells 



