624 MINNESOTA BOTANICAL STUDIES. 



THE SEASON OF 1899. 



Although Trestle island was visited during the winter of 

 1898-99 and was also observed during the spring and early 

 summer of 1899, I shall at once proceed to a midsummer sketch 

 of it, as it appeared from August 14 to 16, 1899. 



Compared with the preceding season, the West section had 

 this time changed most rapidly and radically. The mud flat of 

 fourteen months ago was now a thicket of young peach-leaved 

 willows (Salix amygdaloides). The cotton woods (Populus 

 deltoides) and the aspens (Populus tremul aides] so conspicu- 

 ous last year were now hidden by the willows, which had grown 

 so large that a herd of cattle or horses would have been com- 

 pletely concealed. Although the high railroad embankment 

 was not more than forty feet from the spot where I wrote up 

 my notes, I could only get glimpses of it along the sky line. 

 Within fourteen months there had grown from the tiny, wind- 

 carried willow seeds a thicket of trees that were large enough 

 to completely shade my paper and exclude the southwest 

 breeze, while two of the young trees were stout enough to 

 afford me a secure and comfortable back rest. One of them, 

 by actual measurement, was n feet 3 inches high and had a 

 diameter of i^ inches at a distance of four inches above the 

 ground. All the larger trees of this species were approxi- 

 mately of that size and showed a growth of about five feet for 

 the season. A few of the cottonwoods not standing very close 

 to any Salix amygdaloides were about as tall, but not as thick 

 as the Salix, while the aspens and three or four other species of 

 willow were much smaller and showed only a growth of about 

 three feet for the season. It was clear that the peach-leaved 

 willow would be the dominant plant on this section. It has 

 clearly won the battle against the cottonwoods ; and other trees 

 and herbs will occupy a subordinate position. The West sec- 

 tion is a willow island. 



Lack of space forbids to enlarge upon the herbs and grasses 

 on this section, but it should be mentioned that a fringe of cat- 

 tails {Typha latifolia] and arrowheads (Sagittaria latifolia) is 

 forming on the lake side of the West section. These plants 

 grow there in 6 to 12 inches of water, where the whitish marl 

 was not raised above low water level although it was elevated 

 considerably. 



