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22
ZYGNEMATACEAE
REPRODUCTION BY APLANOSPORES
53. Aplanospores blue 54
53. Aplanospores or akinetes yellow to brown 55
54. Spores punctate with irregular elongate
pits (S7. Z. borzae
54. Spores scrobiculate, diameter vege-
tative cells 21-23 M 80. Z. jrigidum
54. Spores scrobiculate, diameter vege-
tative cells 33M 85. Z. hypnosporum
54. Spores smooth 84. Z. quadrangitlatum
55. Diameter vegetative cells less than 25 /a 56
55, Diameter vegetative cells 26 to 36 /i. 57
55. Diameter vegetative cells greater than 36 ^ 58
56. Vegetative cell diameter 1 5-1 8 m,
spores dolioform 94. Z. mlrificum
56. Vegetative cell diameter 16-21 /i.,
spores ovoid 81. Z. spontanettm
56. Vegetative cell diameter 17-20M,
spores cylindric 86. Z. schwabei
56. Vegetative cell diameter 20-22 ft,
spores ellipsoid 93-
-^- ellipsoideum
57. Median spore wall scrobiculate 82. Z.cylindricum
57. Median spore wall granulose 88. Z. subcylindricum
57, Median spore wall pitted 95- ^- khannae
58. Diameter vegetative cells 40-42 /x,
spore cylindric 89. Z. irregulare
58. Diameter vegetative cells 44-54 m,
akinetes 83. Z. sterile
The following species have been found in some collections producing
both zygospores and aplanospores: Z. catenatum, Z. circumcarinatum,
Z. collinsiantim, Z. cruciatum, Z. excrassttm, Z. jantcum,
Z. giganteum, Z. insigne, Z. leiospermum, Z. neocru datum, Z. pectinatum,
Z. peliosporum, Z. stellinum, Z. terrestre, and Z. synadelphum.
Descriptions of Species
I. Zygnema oveidanum Transcau 1934. Trans. Amer. Micros.
Soc. 53, p. 208, PI. 17, Fig. I.
Vegetative cells 8-12 ^ x (32-) 35-40 (-68) m; conjugation scalariform;
zygospores formed in the conjugating tubes, ovoid to globose, 12-15/1 x
15-30 ju; median spore wall colorless to yellow, punctate; pits about lu
in diameter. (PI. II, Fig. 3.)