141 



OBSERVATIONS ON THE FORMATION OF ALGAL 



PAPER 



By John W. Harshberger 



A few years ago my attention was called to a felted mass of 

 material collected in several places in eastern Pennsylvania on 

 the margins of ponds, lakes, and reservoirs, as well as on Lake 

 Champlain. A microscopic study of this material showed me 

 that it comprised the matted remains of green algae and diatoms 

 that had been blown together by the wind, and later dried, so as 

 to form sheets of paper. The notes below give the results of my 

 investigation. 



Samples of pond paper were submitted to me by Dr. G. F. 

 Gilbert, of Honey Brook, Pa., where it was formed in the reser- 

 voir of that place, and by Miss Elizabeth Woolman, of Lans- 

 downe, Pa. The paper from Honey Brook was formed by the 

 matting together of oak leaves, some pretty well decomposed, 

 others dry, brown and firm, and matted filaments of Oedogonimn 

 sp., with numerous detached oogonia and oospores, Diatoma inil- 

 gai'is, Bianillcria sp., Tabellaria floccosa, Tribonenia bombycimiVL, 

 T. bombyci)iiun forma minus and EiiasiriLm simplex. 



The felt submitted by Miss Woolman (now Mrs. Aldrich Pen- 

 nock) was much finer in texture and more uniform in appearance. 

 It consisted of an almost pure mass of the filaments of Oedogo- 

 niiun fragile . None of the filaments of this mass were in the fruit- 

 ing condition, nor were the cells so badly collapsed. 



An asbestos-like felt was received from Dr. Charles H. Frazer 

 from W. C. Richardson, collected at Essex, Lake Champlain, in 

 June, 1904. This asbestos-like felt was found to consist of 

 frustules of a Navicida, the species of which I have been unable 

 to determine. In addition to Navicida, I found a few disjointed 

 segments of Tabellaria floccosa, together with a few filaments of 

 an undetermined alga which assisted in the formation of the 

 felted mass. 



Through the courtesy of Dr. Adolph W. Miller, I received 

 some algal felt from Dr. H. M. Freas, of Philadelphia, gathered 



