106 Journal of the Mitchell Society [August 



all exhibiting mycorhiza. Bower (1) says that the seedlings of the 

 common heather {Calluna vulgaris) will not develop roots until in- 

 fected with the right fungus. Our plant, however, clearly forms the 

 ectotrophic mycorhiza, and no attempt will be made in this paper to 

 review the extensive literature on the endotrophic mycorhizas. 



In 1922 McDougall (12) reported a Cortinarius sp. with yellow 

 mycelium forming mycorhiza on Picea rubra and one with white my- 

 celium on Abies Balsamea. He also described a tubercle-like compound 

 mycorhiza on seedlings of Pinus strobus from Maine. He says: "So 

 far as I am aware no structures at all similar to these have ever before 

 been described. Coral clusters of mycorhizas containing large clusters 

 of rootlets are well known. Moller reported a cluster on a spruce 

 seedling that, judging from his illustrations, must have contained al- 

 together a total of a hundred or more rootlets and I have frequently 

 seen comparable if somewhat smaller clusters on the roots of oak and 

 hickory species. The case that we are reporting here, however, in 

 which the rootlets are bound together by the mycelium into a com- 

 pact tubercle seems to be entirely unique." The nodules were pale 

 yellow or buff in color and varied from one to four millimeters in 

 diameter. No sporophores were found. His sketch of a cross section 

 of this compound mycorhiza agrees very well with sketches of our 

 plants. There is also an agreement in color ; but we find plants much 

 larger, up to 1.5 cm. in diameter, and we do find sporophores. There 

 is quite a possibility that McDougall had the same plant that we have 

 found on Pinus echinata and Pinus taecla. 



Dr. Collier Cobb (3) in his paper entitled The Forests of North 

 Carolina mentions the presence of minute fungi attached to the roots 

 of Pifius taecla on Hatteras Island and suggests that the trees may be 

 aided by their presence. I have shown our plants to Dr. Cobb and 

 he is of the opinion that they are the same plants observed by him on 

 Hatteras. He say that he mentioned them m a talk entitled "Plat- 

 teras Island" before the 44th meeting of the Blisha Mitchell Scientific 

 Society at Chapel Hill, December 9, 1902; and in one entitled "Hat- 

 teras Island and Its Shifting Sands" before the Association of Ameri- 

 can Geographers in New York in 1906. If McDougall's plants from 

 Maine and those observed by Cobb on Hatteras Island are Rhizopogon 

 parasiticus, then this species has quite a wide range. It is so easily 

 overlooked that closer observation may show it to be not uncommon 

 generally. 



