6o 



TUFTS COLLKGE STUDIES, VOL. IV, No. 7 



38. Oogoninm oboviform. 28. Oe. obovi/orme. 



38. Oogonium snboboviform to obovi form-ellipsoid. 39. 



39. Male plants stouter than female. 29. Oe. pachyandrium. 



39. Male plants more slender than female. 30. Oe. grande. 



40. Oospore globose. 41. 



40. Oospore ellipsoid. 53. 



41. Division of oogoninm median or subtnedian. 42. 



41. Division of oogoninm superior. 47. 



42. Cells with spiral markings. 32. Oe. punclato-slriatum. 



42. Cells without spiral markings. 43. 



43. Oogonium with a whorl of projections. 

 43- Oogoninm without whorl of projections. 



44. Projections mammiform. 



44. Projections blunt-conical. 

 45. Monoecious. 

 45. Dioecious. 



46. Oospore 20-24 M diam. 



46. Oospore 25-29 M diam. 



46. Oospore 32-38 n diam. 

 47. Monoecious. 

 47. Dioecious. 



48. Vegetative cells with 3 nodulose swellings. 



48. Vegetative cells cylindrical. 

 49. Oogoninm pyriform or subpyriform. 

 49. Oogonium oboviform-globose to subglobose. 



50. Oogonium 26-30 M diam. 



50. Oogonium 40-45 M diam. 

 51. Oogoninm distinctly swollen. 

 51. Oogonium little swollen. 



$2. Vegetative cells 15 M diam. or less. 



52. Vegetative cells 16 M diam. or more. 

 53. Membrane of oospore smooth. 

 53. Membrane of oospore ribbed. 



54. Oogonium oblong-ellipsoid or biconic. 



54. Oogonium pyriform. 

 55. Ribs 30-35. 

 55. Rib* 15-19. 



56. Vegetative cells 3-7 M diam. 



56. .Vegetative cells 10-18 M diam. 

 57. Oogonium biconic to subglobose. 

 57. Oogoninm elongate-ellipsoid. 



58. Oogoninm 14-19 M diam. 



58. Oogoninm 23-28 ** diam. 

 59. Dwarf males pluricellnlar. 

 59. Dwarf males unicellular. 



44- 

 45- 



388. Oe. tttantntifcrum. 

 38b. Oe. Itzigsohnii. 

 77. Of. actnandriuni. 

 46. 



78. Oe. consociatutn. 

 33. Oe. Howardii. 

 79. Oe. pratense. 

 48. 



38. Oe. Pringsheimii. 

 41. Oe. nodulosutn. 

 49- 

 50. 



34. Of. l*ithophorae . 

 71. Oe. pyriforme. 

 52. 



37. Oe. autumnale. 

 35. Oe. cri sftum. 

 36. Oe. obesum. 

 54- 

 55- 

 56. 



. Oe. sanctae-thoniae. 

 42. Oe. nob He. 

 . Oe. pauco-costatum. 



57- 



39. Of. Ahhtrandii. 

 7oa. Oe.pusillum. 

 58. 



40. Oe. gracillimu m . 

 81. Oe. obloHgum. 

 60. 

 87. 



