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ZYGOGONIUM 65
3. Zygospores 15-26/U, x 20-36 ju,, sporangium
suture indistinct i. Z. ericetorum
3. Zygospores 13-17 m x 19-32 /x, sporangium
suture prominent 2. Z. mirabile
3. Zygospores 20-25 ju, x 18-25 /"-, sporangium
with pectic wall 3- 2^- pectosum
4. Zygospore median wall scrobiculate or punctate 5
4. Zygospore median wall with pits, or marginal arched ridges 6
5. Zygospores without distinct suture, median
wall punctate 8. Z. punctatiim
5. Zygospores without distinct suture. ... 9. Z.heydrichii
5. Zygospores in sporangia having collars
at both ends 14. Z. stephensiae
5. Zygospores with distinct suture 10. Z.sinense
6. Zygospores with scattered pits on
median wall 1 1. Z. exuvidlijorme
6. Zygospores with arching ribs on
one side of suture 12. Z. plal^ountiosporum
7. Spore walls probably smooth at maturity 8
7. Spore walls not smooth when mature 9
8. Diameter vegetative cells 10-14 /n,
spores usually terminal 7. Z. kumaoense
8. Diameter vegetative cells 12-20^,
spores usually lateral 5. Z. talguppense
9. Diameter vegetative cells 8-12/1, spore
wall verrucose 4. Z. hansgirgii
9. Diameter vegetative cells 16-20 ij^, spore
wall scrobiculate 6. Z. capense
Descriptions of Species
I. Zygogonium ericetorum Kiitzing 1843. Phycologia Generalis,
p. 446.
Vegetative cells 12-33 m x io-ioom; chromatophores 2, stellate, pillow-form
or indefinite, each with a central pyrenoid; filaments branched
or unbranched; conjugation scalariform. Zygospores develop within
definite sporangia formed by the conjugating tubes and cut oflf by a
wall from the adjoining gametangia. Zygospores ovoid or ellipsoid,
1 5-26 /J. X 20-36 /i, thick-walled, smooth; aplanospores globose or ovoid,
occupying only a part of the original cell, 15-20 /x x 15-40 /x; wall
smooth. (PL X, Figs. 10-16.)
United States: Known to occur on acid soils, in ponds and peat bogs
throughout the coastal plain from Maine to Mississippi, and in Ohio, Mich-