On the Fructification of Seeds. 85 
most strange and contradictory imaginable; since the nowishing 
vessels are visibly made for the latter purpose ; but leaves from 
the first moment yield their oxygen, as may be known by their 
dissection. As to the manner of the impregnation of the seeds, 
I have tried them in almost every class and order, but never dis- 
covered any difference in this respect. But I am now trying in 
different seis of plants whether they vary in any way; such as 
fresh-water plants, sea-weeds, sand-weeds, &c. 
In my next letter I shall give the progressive passage after the 
impregnation of a plant to its growth in the earth, with ail 
the intervening steps, never before shown, and most truly cu- 
rious. 
it is always better, for dissection, to trust to the indigenous or 
fiowers of the country; it is certain that, the spiral not being so 
perfect in exotics, its functions are not performed so well. [ 
have now before me above forty different sorts of pistils, but they 
all proclaim the same law and mode of proceeding.’ The stigma 
of the Pentandria digynia plant is a very curious one, formed 
of bubbles, which visibly show the absorption of the powder and 
its reduction into the juices which tint the interior, through 
the trough of the style (see fig. 9); as is also the pistil of the 
Glecthoma (fig. 9X), which has long hairs, to whieh the balls 
adhere till they explode, yielding their extremely fine dust by a 
sudden apparent electrical effect, when the absorption takes 
place, and it is quick and immediate. 
It is quite a mistake of Gertner to sav, that when barren and 
fertile seeds are mixed together in the same seed-vessel, the 
whole becomes nugatory. There is no seed-vessel that has not 
hoth sorts in the same pericarpium; but they are imperfect from 
different causes, easily perceived : from the heart not reaching 
the seed,— from the seed not being impregnated ; that is, 
the line of life not passing through ihe corculum,— from the 
nourishment dying away before it can reach the seed. Every 
seed-vessel shows at first many seeds, even those that never per- 
fect but one or two. This is admirably seen in the chesnut, 
which almost always has six when the pericarp is under the bud; 
they go oif by degrees, and at last one or two only are completed. 
As to the proof that the mixture of the pollen is the cause of the 
impregnation of the seeds, let the evidence be only fairly ex- 
amined, and no one can disbelieve it, A bed of female plants 
of the dioicous tribe has beenset, and kept from the approach of 
staminiferous flowers, and perfect seeds have notwithstanding 
been got from it. This has been brought forward as a proof of 
the falsehood of the sexual system,—without the female plants 
being examined, to see whether there were not males concealed 
P3 among 
