SPIROGYRA 143 



115. Diameter vegetative cells 130-150 /x, 

 about 8 chromatophores, median spore 



wall verrucose 171. 5. heeriana 



116. Diameter vegetative cells 150- 



170 /A, 6-7 chromatophores 172. 5. crassiuscula 



116. Diameter vegetative cells 170- 



200 jn, 6-7 chromatophores i73- '^- tnegaspora 



116. Diameter vegetative cells 150- 



162 /x, 9-10 chromatophores 174. iS*. lenticularis 



CONJUGATING TUBES FORMED BY THE MALE GAMETANGIA; SHORT 



FERTILE CELLS OFTEN ALTERNATING SINGLY, OR IN PAIRS, 



WITH LONG STERILE CELLS 



117. Diameter vegetative cells less than 30 /^ 118 



117, Diameter vegetative cells between 30 jn and 40 /a 125 



117. Diameter vegetative cells more than 40 /x 128 



118. Zygospores ellipsoid 119 



1 18. Zygospores ovoid 124 



119. Diameter vegetative cells less than 15 a"- 120 



119. Diameter vegetative cells 15/^ to 24/i. 121 



119. Diameter vegetative cells more than 24 /j. 123 



120. Median spore wall smooth 180. 5. liana 



120. Median spore wall coarsely punc- 

 tate 181. S. prescottii 



120. Median spore wall reticulate to 



punctate 179. 5. taylorii 



121. Spores with median wall smooth 122 



121. Spores with median wall coarsely 



punctate 183. S. collinsii 



121. Spores with median wall irregularly 



pitted 185. S. sirogonioides 



121. Spores with median wall reticulate. . . 186. S. lushanensis 

 121. Spores with median wall finely scro- 



biculate 271. S. sibirica 



122. Fertile cells inflated on the con- 

 jugating side 18. 5. gibberosa 



122. Fertile cells inflated both sides.. 182. S.chenii 

 123. Median spore wall coarsely punctate, 



diameter vegetative cells 24-30 a^ 184. S. punctata 



123. Median spore wall irregularly retic- 

 ulate, diameter vegetative cells 27-33/^ 187. S.esthonica 



