ISOACHLYA 83 



with a few, usualU' i or 2. inconspicuous pits, or often with no pits visible. 

 Antheridial branches diclinous, usually 'atcral from small threads in 

 the neighborhood of oogonia. sometimes from branches which bear 

 oogonia, very clear and hyaline, delicate, quickly disappearing after 

 the formation of the antheridia; antheridia absent on most of the first 

 oogonia, present on a varying proportion of the later ones, usually few, 

 varying from almost none (less than Yz of 1%) to about 10% or 15% 

 or even 45*^^ on grul)s, cylindrical or tuberous, laterally applied and 

 partly embracing the oogonia, not wrapping them about, easily visible 

 after their threads disappear; antheridial tubes formed. Eggs usually 

 1-6, rarely 8 or 12, centric, very variable in size, 11-33;!. in diameter, 

 most about 22-30^, extremes often mixed in the same oogonium. Gem- 

 mae not very abundant, sub-spherical or pyriform or irregularly rod- 

 shaped, often in moniliform chains. 



Rare; found in Chapel Hill only four times: in the marsh opposite 

 the cemetery, January 12, 1917, and again on April 30, 1918; in the 

 branch at west end of Battle's Park, February 2, 1918; and among 

 decaying leaves in a little branch behind Dr. Archibald Henderson's 

 house, March 8, 1918. 



Kauffman found his plant at Ann Arbor, Mich., November 2^^, 1920, 

 in shallow water over peat-like organic remains, shore of First Sister 

 Lake and in a pool of sphagnum near by. He read a diagnosis of his 

 plant as a species under Isoachlya, but without specific name, before the 

 Botanical Society of America, and I found on receiving the manuscript 

 from him that his plant and mine were the same with perhaps a varietal 

 dift'erence. We then decided to publish this jointly. The diagnosis as 

 gi\en abo\e by me is from the Chapel Hill form. It will be noted that 

 the two forms dififer in no important respect except in the maximum 

 numl^er and size of the eggs in the Chapel Hill form. 



This is easily distinct from our other North Carolina species, and 

 outside of its own genus seems nearest S. torulosa, as described by de- 

 Bary and by Fischer. It differs from the latter in the much smaller 

 proportion of chained to single oogonia, in the antheridia being only 

 diclinous and apparently more numerous, and in the larger average size 

 of the eggs. In 5. torulosa the oogonia are said to be almost always in 

 torulose rows, while in our plant the single ones are far more common. 

 Humphrey says of the oogonia "commonly in torulose series," but of 

 two slides of his labelled S. torulosa one shows only a few such rows, 

 most of the oogonia being single as in our plant, and with a good many 

 antheridia, while the other looks more like /. monilijera, with brown- 

 walled oogonia in chains that are separating from each other. The 

 first mentioned slide may be the present species but the oogonia have 

 many more pits, and its identity is doubtful. It is probable that on 



