ARCEUTHOBIUM IN WISCONSIN. 



By S C. Wadmond. 



FOR years, the writer has had a speaking acquaintance with 

 the so-called "witches' brooms" on Coniferous trees, but 

 had never felt much interested in them from the standpoint of 

 a student of phanerogams. Last year, however, (1907) we 

 spent a week in the vicinity of Gordon, Douglas Co., in the ex- 

 treme northwesterly corner of Wisconsin, in company with 

 Dr. J. J. Davis of Racine, who was making a special search for 

 the various species of fungal growths which cause these cur- 

 ious deformations. 



One morning we had worked our way into a black 

 spruce swamp, the Doctor examining such witches' brooms as 

 were at all accessible. One "broom" in particular hung tempt- 

 ingly on a small spruce, and it was an easy task to bend the 

 tree down sufficiently to examine the bunches of closely packed, 

 slender branches, quite resembling a broom made of twigs. 



At first glance, and without the magnifier, it seemed to 

 bf afifected by the same fungus which Dr. Davis had observed 

 and collected on other witches' brooms earlier in the week, and 

 he called the writer's attention to what seemed to be a swelling 

 of the tissues, and the formation of a great number of little 

 vegetative bodies, magenta-red in color, and proliferous, on the 

 portion of the broom which showed living twigs. A closer ex- 

 amination, however, under the magnifier, made us quite certain 

 that we had in hand, not a parisitic fungus, but a parasitic 

 phanerogam, and if the latter, we knew it must be Arceutho- 

 bium which both of us knew from herbarium specimens, al- 

 though neither of us had ever seen it in the field. I was just 

 that certain of it that I took enough material to almost glut my 

 collecting case. We needed only to get back to our hotel and 

 consult our Illustrated Flora to know absolutely that we had 

 found the little mistletoe Arceuthohium pusillum, a noteworthy 

 find, not only because it added a new and extremely rare and 



