1 886.] NEW-YORK MICROSCOPICAL SOCIETY. 3 



of the stem it appeared stronger, showing that on the bark of 

 the younger wood it found a more congenial habitat. Under 

 the microscope the masses were quite flat, and among them were 

 observed quantities of a white, granular matter. On the Hibiscus 

 {Hibiscus Syriacus) the growth was of the finest character, and 

 hyphge were observed in a budding process, having from two to 

 six branching cells ; below the hyphae were the large masses of 

 Protococcus cells which had been produced by fission, mostly in 

 twos and fours, standing out in projecting clusters. In this 

 specimen and in many others examined, several brownish buds, 

 probably of another species of Protococcus, were found, showing 

 growth by gemmation as well as by fission, and with abundant 

 hyph^. 



On the White Birch {Betula alba) the growth is chiefly 

 confined to those broken portions of the bark which 

 presen't a rough surface for the retention of moisture and the 

 collecting of foreign matter. Under the microscope the growth 

 was seen to be scanty, yet the hyphae-bearing cells were abundant. 

 On the Hemlock ( Tsuga Canadensis') it was very abundant and 

 of a bright yellow green, and the gelatinous mass was so strong 

 that when placed under the cover glass of a slide in water they 

 were with difficulty separated. On the Deciduous Cypress ( Taxo- 

 dium distichum) the plant was more vigorous than on any other 

 coniferous tree, the soft spongy bark being well adapted for 

 its growth. On the west side of the Park walls, along Fifth and 

 Eighth avenues, the growth is so abundant that the coping and 

 three tiers of Nova Scotia sand-stone have a bright green color. The 

 next tier, of North River blue-stone, has very little upon it, and 

 on the basal course of Gneiss none is apparent, yet on the mortar 

 it is abundant. On the Terrace north of the Mall, the Nova 

 Scotia sand-stone on the northern and the western exposures 

 is covered with a rich growth, and no doubt this is one of the 

 causes of the disintegration of the stone. The Protococcus hold- 

 ing moisture, and the expansion by freezing breaking down the 

 small particles of stone. On the south side of the transverse 

 road the growth is abundant, while on the north side but little 

 is seen. 



In treating the trees in the Central and other Parks of New 

 York with polysolve, a preparation used for the destruction of 



