THE AMERICAN BOTANIST 89 



uplands down the valley. Since then the track has been 

 changed, but the flat, vacant, unkept roadbed still lies along the 

 sides of the ravine surrounded by dense woods. The trees 

 have not yet had time to grow up and most of the roadbed is 

 occupied by jungles of blackberries. Here and there the drain- 

 age is not good, and small pools of water have collected. To 

 these have migrated bulrushes blue flags, cat tails, and several 

 other swamp-loving plants, which look decidedly out of place 

 on the steep hillside a hundred feet above the valley. The 

 most interesting plant of all is the water cress, (Radicula nas- 

 turtium-aquaticum) , which is growing luxuriantly in one small 

 shaded pool. The water cress has small seeds, and we may 

 suppose that they were brought from some other pond in mud, 



adhering to the feet of birds. Elsewhere along the same em- 

 bankment prairie plants have established themselves, and black- 

 eyed Susan, prairie coneflower and tick trefoil grow only a 

 few feet away from hepaticas and wild hydrangeas. 



Another Interesting Migration. — The University 

 forestry plantation has afforded many illustrations of the 

 movement of plants from one place to another, and scarcely 

 a year elapses without one or more new invaders appearing. 

 Most of these are carried by the birds, which come in enor- 

 mous numbers to the forestry to roost ; many others have seeds 

 distributed by the wind, while some cannot be accounted for. 

 The particular case in point is the twayblade, (Liparis lili- 

 foiia), a single plant of which appeared and bloomed during 

 the spring. Twayblade has been found in this country, but 

 not for many years. It certainly does not grow within a ra- 

 dius of ten miles from the forestry, and has been considered 

 extinct within the county. Just where it came from, or how 

 its seeds travelled, are matters that can not now be explained. 



