BULLETIN OF THE BUSSEY INSTITUTION. 291 
cent elaborate and methodical trials of Haenlein* at Tharand, that 
the seeds of many other kinds of weeds are extremely sluggish 
and difficult to germinate; and that the results of my old experi- 
ments are perhaps not wholly worthless, since they add a few new 
particulars to Haenlein’s list. The only plant common to his 
trials and my own is the knot-weed (Polygonum persicaria), the 
seeds of which behaved with him much in the same way they did 
with me. In Haenlein’s trial 13 per cent of the seeds of this plant 
germinated in the course of eight days; and, in an earlier experi- 
ment by Nobbe and Haenlein, 7 per cent germinated in fifteen days. 
Although it has been made plain by the work of the Tharand 
observers that much more than a few days, or months even, is 
needed in order to determine whether a given sample of weed- 
seeds is capable of germinating; and although it has been made 
manifest that there are other conditions and circumstances beside 
the influence of air, warmth, and moisture, which are essential to 
the speedy germination of many kinds of seeds; there is still small 
reason to doubt the conception that tolerably high temperatures 
must be essential to success in many instances, and there are some 
reasons for believing that abundant warmth, at the moment of 
germination, may be of paramount importance in certain cases. 
Several of the practices of gardeners enforce this idea; such, for 
example, as the habit of ‘‘ starting” in hot-beds or in special 
boxes which can be kept warm, the seeds of many plants of south- 
ern origin, and the steeping also of various kinds of seeds. I have 
myself noticed that some of our New England farmers habitually 
resort to artificial heat for germinating the seeds of squashes. An 
approved method is to place in a milk-pan a quantity of the damp 
vegetable mould that collects in hollow apple trees, through decay 
of the wood, to sow the squash seeds in this earth, and to place 
the pan in a warm position near the kitchen stove until the seeds 
have started,.when they are transferred to the soil of the field. 
So, also, the practice, common among gardeners, of putting cer- 
tain leguminous seeds into boiling water, to awaken their dormant 
energies, may perhaps point to the existence, for all seeds, of a 
definite, necessary temperature to which the seeds must be brought 
before the act of germination can begin. It would be but natural 
that this starting temperature should be exceptionally high in the 
case of tropical and hot-weather plants. 
February, 1881. 
* ‘* Pie landwirthschaftlichen Versuchs-Stationen,” 1880, 25. 465. 
