The Conjugation of Spirogyra crassa Kg. 
By Epwin BincHaM COPELAND 
On an afternoon in September, 1900, the writer collected in a 
stagnant cut-off on Cheat River in West Virginia some Spirogyra 
so large that its conjugation was very evident to the naked eye. 
It was fixed in Flemming’s fluid and preserved in alcohol. When 
it was examined and determined later, preliminary to class use, it 
was found to have some characteristics that are probably worth 
reporting. 
Different species of Spirogyra vary in the intensity with which 
they possess distinct sexuality, as male or female plants. In all 
of them the cells show a difference in behavior, in that one is 
recipient, the other active, which is a marked advance over related 
genera in which the zygospore is formed midway between the 
gametes. But in some species the cells of a single. filament con- 
jugate in pairs, the conjugating tube passing around the trans- 
verse wall; in this case the filament as a whole is without sex. 
When the conjugation is between the célls of parallel filaments 
it is usually altogether in ‘ont direction, one filament acting as 
female and the other ag-male:’ But in such cases filaments some- 
times occur which if traced far enough are found to bend about 
Onto, and conjugate with, themselves, being female in one part, 
male in another.. Such cases suggest that where a distinction of 
the Sexes is just beginning to appear, sex may be a relative quality ; 
_ifone part of a filament can be male with reference to another part 
as female, why might not a filament act as male with reference to 
one of its neighbors, but female with reference to another. In this 
S. crassa material sex is a positive quality of the filament. I have 
*xamined a great number of instances of polygamy and polyandry, 
Cases in which a long filament conjugated at different places along — 
= length with several others. I have never found « filament 
conjugating with itself, nor a single instance of a filament whose 
“eX Was not constant in its numerous alliances. Often three fila- 
ments were in contact, each with both the others; one would conju- 
_ Sate with both others indiscriminately, all the cells of both the others 
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