SPIROGYRA 149 



178. Chromatophores i to 3 179 



178. Chromatophores 2 to 4 180 



179. Median spore wall single 254. S. nawashini 



179. Median spore wall double 255. S. tetrapla 



180. Chromatophores (2-) 3-4, spore 

 diameter 45-75 M, aculeate-retic- 

 ulate 252. S. inconstans 



180. Chromatophores 3-4, reticulate- 



spinose 251. S. acanthophora 



180. Chromatophores 2-4, spore diam- 

 eter 52-62 /a, mammillate-aculeate 253. S.borysthenica 



180. Chromatophores 2, spore diam- 

 eter 42-50 Ai, median wall double 264, S.crassispina 



181. Chromatophores 2 182 



181. Chromatophores (i-)2-3, diameter 



spore 45-60 At, median wall double. . . 256. S. reticulata 

 181. Chromatophores 4-3, diameter spore 



52-71 ju., median wall double 258. S. crassivallicularis 



182. Spores, diameter 39-45 fi, median 



wall single, reticulate 257. S. regularis 



182. Spores, diameter 45-55 M, median 



wall double, inner granulate 259. S. granulata 



182. Spores, diameter 51-55/^, median 



and outer walls double 260. S. quinquelaminata 



182. Spores, diameter 46-68 a^, median 



wall double, reticulate 261. S. pseudogranulata 



REPRODUCTION WHOLLY OR MOST COMMONLY BY APLANOSPORES 



183. End walls plane 184 



183. End walls semireplicate, diameter veg- 

 etative cells i2-i/\fj- 198. S. narcissiana 



183. End walls replicate, diameter vegeta- 

 tive cells 24-28 Ai 234. S. articulata 



184. With I chromatophore 185 



184. With 2 or more chromatophores 186 



185. Sporangia cylindric, aplanospores 



ovoid 31- '^- oltmannsii 



185. Sporangia enlarged or slightly inflated 29. S. mirabilis 



185. Sporangia and sterile cells often in- 

 flated 38. 'S. aplanospora 



186. With 2 to 3 chromatophores in 



each cell, spores ellipsoid 65. 5. maravillosa 



