628 MINNESOTA BOTANICAL STUDIES. 
trees that had grown scattered amongst the weeds were found 
to have been fire-killed, but about one-half of their number had 
grown out again near the ground. ‘The larger ones in the south 
corner had not been killed, because there the weeds had not 
grown as thick. 
Patches of the perennials, Elymus canadensis and a few other 
grasses, as well as goldenrods, sunflowers and nettle were coming 
out vigorously. The rice cut-grass, however, although it seems 
to be perennial, had a very poor start. On close examination 
numerous seedlings of annuals were found, but all looked 
brownish and sickly on account of the dry weather and the 
glaring sunlight. Although most of them were not readily 
identified, I recognized the following without difficulty : 
1. Polygonum sp. 
2. Mentha sp. 
3. Carduus lanceolatus, the seedlings of which looked quite 
green and vigorous. 
4. Lactuca sp. 
5. Brassica nigra. 
6. Chenopodium sp. 
The spring and summer of 1899 were excessively dry in this 
region so that, since January Ist a continued accumulated defi- 
ciency of rain of over 4 inches was reported from May 31st 
to August 31st. About June roth another -new factor, one that 
is able to destroy all plant life not perennial or not armed in 
some way, appeared on the scene—ca/é/e, a large herd of 
hungry dairy cows. In their search for green grass they had 
passed over the dried-up marsh and along at the foot of the 
embankment and had discovered the East section of Trestle 
island. 
In the end, however, bovine instinct for plant selection proved 
of some interest, for, when after an absence of over two months, 
I visited the place again about Sept. roth, there was a closely 
cropped, rough, much trampled piece of pasture. Where a 
year ago about 60 different plants had grown in wild exuber- 
ance, only about 40 cropped and crippled trampled species were 
to be found* and only asingle one of these bloomed and flour- 
ished in large numbers, the formidable armed thistle, Carduus 
* About 30 species of the list of August 16, 1899, had survived fire and cattle 
and about 10 species were found that do not appear on the list of August 16, 
1899. 
