WITCHES' BROOM ON THE LOCUST. 83 



stone places, the shrubby, yellow Potcntilla fruticosa forms a conspicu- 

 ous feature falling- down over the rocks. Growing in similar but more 

 shaded places near the water-line, the white Siillivantia Sullivantii is 

 found in abundance. Likewise growing in crevices and straggling 

 down over the perpendicular surfaces of the sandstone river-faces, 

 Prof. L. S. Cheney and the writer found early in June of last year 

 a dwarf shrub with rather showy, violet or purple, fragrant flowers. 

 After several vain attempts, a fine specimen was obtained. A hasty 

 examination indicated that we had a specimen of the Lapland Rose 

 Bay {Rhododendron Lapponicimt). This Rhododendron, according to 

 the manuals, is an alpine shrub not noted as occurring in this part 

 of the country, being reported from the higher inountains of New 

 England and the Adirondacks of New York, and Quebec and Lab- 

 rador to Greenland, thence west through arctic America to Alaska. 

 It was here found in flower a month earlier than the time indicated. 

 Professor Cheney has compared this plant with the herbarium ma- 

 terial of the University of Wisconsin and believes the specimen in 

 question to be properly assigned to this name. Perhaps the climatic 

 changes above cited in connection with the Large-spurred Violet may 

 also offer an explanation of this probably isolated occurrence. This 

 plant is nowhere noted as being found in Wisconsin. 



Much more might be written concerning this unique bit of 

 country and its attractions for the botanist. Certain it is that, ap- 

 proached from almost any standpoint, the Dells will richly repay any 

 one visiting its crags and caiions. 



University of Wisconsin. 



WITCHES' BROOM ON THE LOCUST. 



By C. E. Waters. 



OF the many curious deformations caused by the attacks of fungi 

 on higher plants, perhaps none are more curious than the so- 

 called "witches' brooms." These bunches of closely-packed, 

 slender twigs, occurring on different trees, are caused by 

 species of the genus Taphrina. Other species attack plum trees, 

 causing the hard, hollow "pocket" plums, and still another causes the 

 leaves of peach trees to curl. The mycelium, or vegetative portion 

 of these fungi live in the tissues of the host plant, which they pene- 

 trate in all directions, and in which they pass the winter unharmed, 

 ready to start a new growth at the return of spring. The presence of 

 this mycelium in the woody portions of a tree cause a swelling of the 

 tissues, and the formation of a large number of branches that spring 



