XXXVII. A CONTRIBUTION TO THE LIFE HIS- 

 TORY OF PILINIA DILUTA WOOD AND 

 STIGEOCLONIUM FLAGELLIFERUM KG. 



JOSEPHINE E. TIEDEN. 



While engaged in studying some species of lime-secreting 

 algae, the following paragraph in Dr. Wood's (I) "History of the 

 Fresh- Water Algae of North America/' came under my notice: 

 "Near Belief onte, Centre county, Pennsylvania, there issues 

 from the limestone rocks the largest spring I have ever seen, 

 giving rise to a creek- like torrent, which supplies the city with 

 water, and passes on scarcely diminished in volume. In this 

 spring grows the curious alga under consideration, forming a 

 somewhat lubricous and stony stratum on the stones and rocks 

 in the basin. This stratum is of a grayish-green color, and is 

 quite friable, breaking in the direction of the filaments with 

 the greatest possible readiness. When placed under the mic- 

 roscope it is seen to be composed of filaments whose course is 

 a direct one from the under to the upper surface. They are 

 apparently rigid, preserving their courses, and not being in- 

 termatted. They are composed of cylindrical, conf ervoid cells, 

 and are dichotomously branched, and yet when viewed as a 

 whole the filament and its branches form a sort of fasciculus. 

 The basal cell or cells appear to be globular. When I collected 

 this plant I was forced by circumstances to put the specimens 

 in carbolic-acid water for future study, and, therefore, I have 

 had no opportunity of studying their method of reproduction. 

 I am not altogether satisfied in referring this plant to the Pili- 

 nia, and yet all the most important of the characters given by 

 Rabenhorst are preserved by it. It certainly, however, differs 

 very greatly from P. rimosa Ktz." 



Dr. Wood names the plant Pilinia diluta. His description of 

 it will be given later. 



This promised interesting matter for investigation, and 

 though it seemed improbable that a plant which grew in a spot 

 more than twenty years ago should have been able to maintain 



