290 BULLETIN OF THE BUSSEY INSTITUTION. 
were thrown away. A similar result was obtained on repeating 
the experiment. 
Lappa officinalis, var. major (Burdock). Of 50 seeds placed 
in a saucer on October 11th, two sprouted on October 24th, and 
others thereafter. 
Bidens chrysanthemoides (Larger Bur-marigold). Fifty seeds 
set to germinate came to naught, and were finally thrown away. 
Ambrosia artemisiefolia (Ragweed). An unlimited number of 
the seeds were set to germinate on October 19th. On November 
11th it appeared that only eight of them had sprouted, and that 
most of the remainder were mildewed; and a repetition of the 
experiment gave an equally unfavorable result. 
Setaria glauca (Bottle-grass). 150 seeds put to germinate on 
October 11th came to nothing, and were thrown away. 
These results were so unlike those obtained at the same time 
with various kinds of grain, and with other agricultural seeds, — 
which germinated readily enough, and were especially in such 
marked contrast with the behavior of some barley which I had 
germinated a few months: earlier at the temperature of freezing 
water,* — that I regarded the experiments as failures, and attrib- 
uted my lack of success to the fact that the temperatures at which 
the germinator saucers were kept were by no means high. ‘To all 
appearance these temperatures were too low for the germination of 
some, at least, of the seeds in question. It is to be remembered 
that many of our commonest weeds are tropical plants, and that 
most of the seeds in my experiments (burdock and persicaria, 
perhaps, excepted) came from plants that flourish during the hot 
weather of the later summer months. 
From these considerations, I inferred that both the seeds and 
the plants needed higher temperatures than those at which my 
olass-house was maintained, and that, consequently, they were 
unfit for the proposed experiments. Some of the burdock-seeds 
germinated readily enough it is true, but the growth of the young 
plants is so slow that I was not encouraged to continue to experi- 
ment with them. It appeared as if this biennial plant was, during 
the first year of its life, merely getting ready to grow in the second 
year, hence no further attempts were made by me to induce the 
seeds of weeds to germinate. It appears, however, from the re- 
* «* Bulletin of the Bussey Institution,” 1, 52. This observation has been 
repeatedly made by other experimenters. 
