HOW PLANTS FLEE FROM THEIR ENEMIES: 



SOME REASONS FOR PLANT MIGRATIONS.* 

 By ]V. J. Bcal. 



IN managing a small botanic garden for the past twenty years, my 

 attention has often been forcibly called to many peculiarities of 

 plant growth. An attempt has been made to grow well in suit- 

 able spots in the open air over 2,000 species of hardy plants. 

 These plants were collected in Michigan and elsewhere, from woods, 

 river bottoms, marshes, swamps, open fields where the soil was wet, 

 dry, loam, muck, sand or clay. Considerable knowledge has been 

 gained in person by digging plants in their native haunts and by 

 transferring them at different seasons of the year from one portion of 

 the garden to another. 



Many years ago I started out with the thought somewhat vaguely 

 fixed in mind that I might find a spot congenial to each species and 

 there plant a patch of it and it would thrive for all time to come, or at 

 least for my time. Most of the plants started well and thrived re- 

 markably in their new homes which I had selected, but after two to 

 six years or longer, many of them began to show signs of failing or 

 died outright, notwithstanding all other species of higher plants in 

 each case were diligently kept from intruding, and usually some fer- 

 tilizers were employed. Neither were the plants in the patches al- 

 lowed to crowd very closely, for they were thinned as occasion seemed 

 to require. 



I learned long since that there is no such thing as planting once 

 for all time. There is no such thing as stability, for plants need a 

 change sooner or later and will have it or perish. 



After a few years plants of the mint family of thirty to sixty 

 species began in numerous cases to show lack of thrift. The ground 

 was clogged with thick mats of rootstocks starving for more room. 

 They were thinned, but still they dwindled. A number were affected 

 with rust and others with fungi, and numerous insects had learned 

 where to find them — in fact, seemed to have settled down to live in 

 that bed of plants. The following plants, especially, failed or died in 

 the middle of each plot, and the healthier portions were to be seen 

 about the margins where rootstocks had encroached on new soil: 



Glecoma hcdcracea, Lycopiis sinuatiis, Lycopus Virginicus, Mentha 

 Canadensis, Monarda didyina, Nepeta Cataria, Vleckia nepetoides. 



*iReadat the meeting of A. A. A. S., held in Detroit, August, iSg?.] 



