NITELLA TENUISSIMA. 121 



GROVES in Journ. Bot. XYIII, p. 163, t. 209, f. 14 (1880). 



MULLER in Bull. Soc. Bot. Geneve II, p. 53 (188 L). 



BRAUN & NORDSTEDT Fragrn. Mon. (Jharac. p. 62 (1882). 



SYDOW Europ. Charac. p. 28 (1882). 



BOSWELL Engl. Bot. ed. 3. XII, p. 184, 1. 1904 (1884). 



MIGULA Die Characeen, p. 173, f. 48-49 (1890) ; Syn. Charac. Europ. 



p. 45, f. 36, 37 (1898). 



HOLTZ Characeen, in Krypt. Mark-Brandeiib. p. 76 (1903). 

 PROSPER Carofit. Espafi. p. 72, f. 12, A c (1910). 

 HY in Bull. Soc. Bot, France, LX, Mem. 26, p. 16 (1913). 



N. exigua WALLMAN Forsok syst. Charac. p. 38 (1853) ; Transl. p. 33 



(1856) ? 



EXSICCATA : Areschoug, 394 ; Billot, 1985 ; Braun Rab. & Stiz. 60, 

 103 ; Desmazieres II. 323 ; Groves, 23, 24, 55 ; Giinther, Grab. & Wim. 

 1829, Cent XV (fide Sydow) ; Jack, Lein. & Stiz., 811 ; Lloyd, 421, 422 ; 

 Migula, Syd. & Wahlst., 3, 4, 126, 127 ; Xordstedt & Wahlstedt 41 ; 

 Reichenbach, 100 (in some sets). 



Monoecious. Stem very slender, c. 250 //, thick ; 

 internodes 2-5 times the length of the branchlets. 

 Wliorls usually of 6 short somewhat spreading 

 branchlets. Brancklets of the fertile whorls 3-4 

 times furcate ; primary rays -|-f the entire length ; 

 secondary rays 6-7; tertiary rays 4-6, of which 1-4 

 are usually simple; quaternary rays 2-5 of which 1 is 

 occasionally again furcate with 3-4 quinary rays. 

 Ultimate rays long narrow straight, invariably 2-celled ; 

 lower cell of uniform thickness, usually truncate at the 

 apex and but little broader than the base of the ulti- 

 mate cell; ultimate celllomg narrow acuminate. Oogonia 

 and antlieridia produced at the second and third (not 

 at the first) furcations, often together. Oogonia solitary, 

 at first spheroid or broadly ellipsoid, ultimately some- 

 what narrowed at both ends, when ripe c. 400 //, long 

 (inch coronula), 260 p, broad ; spiral cells showing about 

 9 convolutions; coronula c. 30-40 ju, high, persistent. 

 Oospore roundish-ellipsoid, conspicuously flattened c. 

 200-250^ long, 175-200 /x broad, 100-130 /* thick, 

 showing 7-8 fine but w^ell-defined low ridges ; outer 

 membrane thin, flexible, and translucent, golden-yellow- 

 red, wine-red, or light red-brown, strongly reticulate, 

 with beaded reticulation threads (PI. V, figs. 3-5). 

 Antheridium minute, c. 175/x in diameter. 



