A NEW SPECIES OF SPIROGYRA WITH UNUSUAL ARRANGE- 
MENT OF THE CHROMATOPHORES 
Mabel L. Merriman 
(Received for publication October 24, 192 1) 
In November, 1920, collections of algae in Van Cortlandt Park, New 
York City, revealed a large form of Spirogyra with a peculiar disposition 
of its chromatophores. The collections made at various times during the 
next two months showed the alga freely conjugating and growing in fairly 
pure cultures. It was noted that, whereas in the non-conjugating filaments 
at this time the chromatophores were more or less spirally arranged, no 
case was found of a vegetative cell adjoining conjugating cells where the 
chromatophores were other than parallel in their position. At the time 
it was thought that the plant might be a variety of S. crassa. Subsequent 
collections in May and June revealed S. crassa growing in abundance 
with the new form, both abundantly conjugating, and when seen side by 
side exhibiting characters conspicuously distinct. To date no case has 
been found of the hybridization of the two forms. 
I 
2 
Fig, I. Conjugating filament, with zygospores, of 5. rectispira, from material col- 
lected June, 1921. X 140. Fig. 2. Conjugating filament, with zygospores, of S. crassa 
growing with 5. rectispira. 
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