i 9 2o] CHAMBERLAIN— BOTRYCHIUM 3 8 9 



prothallia are most abundant in the clearing, within 25 m. of the 

 fence, becoming more and more scattered as the woods become 

 denser, while at a distance of 200 m. west of the fence scarcely 

 any plants are found. In this place plants are most abundant on 

 little elevations caused by uprooted trees. When a large tree is 

 blown down, the roots tear up a considerable quantity of soil, so 

 that when the tree decays and disappears there remains a mound 

 with a depression on one side of it. These little mounds of clay 

 soil, scantily covered by moldy humus, seem to be exceptionally 

 favorable places for the germination of spores and the growth of 

 plants. 



A few years ago, before any plots were made, the abundance of 

 plants in this locality suggested counting the number on definite 

 areas. These areas do not correspond exactly to the groups which 

 were plotted later, because only the denser centers of the groups 

 were considered, the more scattered plants at the borders being 

 omitted. Some of the highest countings of plants on given areas 

 are worth recording. On areas of 1 sq. m. there were 15, 20, 29, 

 30, 31, 42, 66, and 106 plants. In the last case the plants were 

 very closely crowded, one cluster of 5 plants occupying a space 

 only 3 cm. sq. On areas of 2 sq. m., there were counted 27, 

 43, 70, and 103 plants; on 4 sq. m., 112 plants; on 2 dm. sq., 7, 

 10, and 16 plants; and on 2.3 dm. sq., 8 and 21 plants. 



In this clearing the groups were rather closely associated, being 

 separated from each other by distances of 1-10 m., with only here 

 and there a plant between. Many of these plants were small, some 

 of them sporelings still attached to prothallia; but in any place 

 where Botrychium is abundant there will be a goodly number of 

 large plants. In such places white patches of the fungus can be 

 ' seen by turning over the leaf mold. 



Aside from noting the grouping and counting the number of 

 plants in a group, little was done with B. virginianum. The same 

 must be said of B. simplex, which was discovered accidentally at 

 Osborn, Indiana, during a search for Ophioglossum. A group of 

 a dozen specimens of this little Botrychium was found on an area 

 of about 1 sq. m. So far as we know, this species has not been 

 reported for the Chicago region. 



