; 
~ 
4 
Lange : REVEGETATION OF TRESTLE ISLAND. 623 
species is very common along the railroad track south of the 
island. These prothallia were little green clumps from ¥% to 
Y% of an inch in diameter and grew mostly on the walls of 
the shaded mud cracks. From many of them one or more 
thin young horsetails were protruding. Although I carefully 
searched the cracks for these prothallia in the springs of 1899 
and 1900, I did not again find a single specimen. In 1898 
they were abundant on both sections of the island, but they did 
not grow on the marl, but only on silt and in silt cracks. This 
silt consisted of a brownish clay and of very fine quartz sand, 
making a compact damp soil. 
The West section was still quite bare early in July, 1898. The 
creviced marl ridges had dried in the sun and exhibited white 
streaks like limestone. These little crags and points were bare, 
but in shaded and sheltered depressions mosses covered much 
of the damp marl; and small cottonwoods, aspens and willows 
were scattered over the whole West section. 
About September roth the aspect of both sections had 
changed, but most markedly that of the East section, which 
was a veritable wilderness of weeds. Its lower portion was 
covered with wild rice, over six feet high. Under the rice and 
also on the higher ground water hoarhound (Lycopus amerc- 
canus), skullcap (Scutellaria laterifolia) and American wild 
mint (Mentha canadensis) formed dense tangles and grew with 
a luxuriance I had never seen before. There were present in 
great confusion nearly all the plants mentioned in the count of 
August 16, 1899, and a few not found at that day. In this 
weeds’ paradise the young willows could be seen, but they were 
not at all conspicuous. No bare ground was now visible on 
this section, but in walking through the weeds, one could not 
avoid frequent stumbling into the cracks. The West section at 
this time presented the appearance of a loose growth of young 
cottonwoods, aspens and willows, with the cottonwoods most and 
the willows least conspicuous, but much bare soil could still be 
seen even from a distance. 
On both sections all the young trees remained green and con- 
tinued to grow until late in the fall. On October 22d they were 
still green but had evidently ceased growing on account of the 
cool weather that had prevailed since the third of the month. 
Of the East section my notes for October 22d say: ‘*A great 
wilderness of dead weeds.” 
