130 ZYGNEMATACEAE 



END WALLS PLANE 

 USUALLY ONE CHROMATOPHORE 



3. Tubes evidently formed by projections from both gam- 



etangia 4 



3. Tubes formed wholly, or almost wholly, by the male gam- 



etangia 117 



4. Vegetative cells with i chromatophore (rarely in some 



cells 2) 5 



4. Vegetative cells usually with more than i chromato- 

 phore (i-) 2-16 46 



5. Median spore wall smooth (outer walls scrobiculate in Nos. 



II, 40, and 41) 6 



5. Median spore wall punctate, scrobiculate, reticulate, or ver- 

 rucose 35 



6. Spores rather uniform (in optical section may appear 

 variable because seen at different angles in different 



cells) 7 



6. Spores distinctly polymorphic when seen from the same 



angle (ellipsoid, ovoid, globose, and irregular) 33 



7. Spores ellipsoid 9 



7. Spores ovoid to cylindric-ovoid 24 



7. Spores globose or compressed-globose 8 



8. Spores compressed-globose, diam- 

 eter 55-65;^^ 152. S. discoidea 



8. Spores globose, or compressed- 

 globose, diameter 85-95 /a i53- '^- sphaerospora 



ONE CHROMATOPHORE 

 SPORES USUALLY ELLIPSOID, MEDIAN WALL SMOOTH 



9. Sporangia cylindric, or enlarged 10 



9. Sporangia inflated on both sides (larger than the spores) ... 19 

 9. Sporangia inflated mostly or only, on the conjugative side. . 14 



9. Sporangia inflated mostly or only, on the outer side 23 



10. Diameter vegetative cells less than 40/14 11 



10. Diameter vegetative cells more 



than 40/4, spore diameter 34-38/u. 6. S.condensata 

 10. Diameter vegetative cells more 

 than 40 /x, spore diameter 42 ju. or 



more 7. 5. varijormis 



10. Diameter vegetative cells more 



than 60/1, spore diameter 60-66/1 33. S.gallica 



