September, 1919 
Slower (Brower 
93 
iiHHiiMiHmiiHiHHiiiiiiiiiHiiiiHiHiiiiiiHiiiiHiHiiimHiimiiimniiiHimmiiiiimi 
T ii ] •: 
How to Hybridize Peonies. 
By A. P. Saunders, Sec’y, in 
Bulletin No. 8, American Peony Society. 
1 ET US ASSUME first that we had the 
task of instructing someone who knew 
J nothing of the structure of a flower, as 
to what the parts of a Peony bloom are, and 
how it is to be hand-fertilized with pollen 
from another variety. 
We should, I suppose, take a single variety, 
as being the simplest, and show him first the 
petals, which, though so conspicuous, take 
no direct part in the development of the seed, 
but are there only to make the flower visible 
and attractive to insects. So, since we are 
to see to the fertilization of the flower our- 
selves, they may just as well be removed. 
The next layer of structures inside the 
petals are the stamens. These are the pollen 
producing organs, and each consists of a 
thread-like stem, the filament, and a yellow 
sac filled with pollen, the anther. When 
the anthers burst, thousands upon thousands 
of microscopic, wheat shaped pollen grains 
are scattered about, and any one of these 
may bring about the fertilization of a seed. 
At the very centre of the flower are the seed 
pods themselves. There are generally three 
of these. They are called carpels, and up- 
on the top of each of them is a sort of 
ridge ; this is the stigma, and it is here that 
fertilization occurs. When a pollen grain is 
placed on the stigma, it sends out a process 
called a pollen tube, which penetrates down 
through the substance of the stigma into the 
pod itself, and there penetrates into one of 
the individual seeds. Through the pollen 
tube the contents of the pollen grain are 
emptied into the seed, fertilizing it and 
causing it to grow into a mature seed. 
In cross-fertilization, therefore, we must 
remove the stamens of the flower on which 
we intend to produce seed, and bring pollen 
from another variety with which to effect 
fertilization. The seed-bearing plant which 
receives the pollen, is called the female, and 
the one from which the pollen comes is called 
the male. 
Our pupil will now want to know some- 
thing of the technique of the process. This 
involves three steps, which I shall describe 
under separate headings : 
Stripping the Flower— The bloom on 
which pollination is to take place must first 
be “ cleaned up. ” When this is done, nothing 
is left of it but the seed pods themseles. We 
first remove with the forceps all the petals, 
because they are of no use and get in our 
way ; then we remove all the stamens, be- 
cause if we do not, the flower will probably 
fertilize itself. Furthermore we must see to 
it that we get the stamens stripped off be- 
fore any of them have burst. That means 
that the flower must be stripped early in its 
history. With double blooms containing few 
stamens or none, we are generally safe if we 
stip off the petals at about the time when 
the bud is unfolding enough to show the 
inside. With single flowers it is usually then 
too late ; these must as a rule be stripped 
well before the stamens are visible. When 
you think the bloom might open out about 
the following day, tear off the petals and 
you will find a tight mass of stamens on the 
inside. Take a look at these with the mag- 
nifying glass, and see whether any have 
burst. If they have, you will almost surely 
find pollen grains adhering to the stigmas. 
At the time when the anthers begin to scat- 
ter their pollen grains, the stigmas become 
covered with a sticky fluid to which pollen 
grains tightly adhere. Hence if you find any 
pollen grains there, give up that flower and 
take one not so far along. 
Peony 
When you get one that shows the stigmas 
apparently free from pollen, and with no 
anthers that have split open, clean it up, 
being very careful to remove every stamen. 
Then take a critical look at the stigmas and 
see that they are (1) free from pollen grains, 
and (2) sticky. If they are not sticky you 
should put a bag over the flower and work 
on it the following day. But assuming that 
they are in good condition proceed to the 
next operation. 
Getting the Pollen and Pollenizing— 
This is a simple matter if you have decided 
from what flower to take the pollen. Rather 
the best plan in my opinion is to have a 
glass vessel in which to place the anthers of 
the variety you wish to use as the male par- 
ent. What the biologists call a Petri dish, in 
a small size, is excellent, as it has a cover ; 
but an ordinary little watch crystal does 
very well. 
Pull off a few of the anthers and set them 
in the glass vessel, then tap it underneath 
so as to shake the anthers up and down. If 
they are in the right condition they will 
shake out a quantity of pollen on the sur- 
face of the glass. Now carry this back to 
the stripped flower, pick up some of the 
spilled pollen on the end of a very small 
sable brush, and dab it on to the stigmas 
until their sticky surfaces are well powdered 
over. If you have no brush, the best plan is 
to pick up an anther in the forceps, and 
rub it on the stigma until some of the pollen 
comes off ; but you will find it all much 
easier and quicker using a brush. Our task 
is now accomplished, and all that remains is 
to protect the bloom from contact with any 
other pollen, and to mark it with a label. 
Bagging and Labelling - Very small pa- 
per bags may be had for almost nothing. 
One of these drawn gently down over the 
fertilized bloom and tied about the stem, will 
protect the bloom from further dangers, and 
may remain until the seed is ripe. So far as 
protection from other pollen is concerned, a 
few days would suffice for that ; for the 
stigmas dry up very soon after fertilization 
has taken place, and when they are dry, 
fertilization is impossible. But if the bags 
are removed, there is danger in the autumn 
that the pods may burst and scatter the seed 
before it is gathered. I generally, therefore, 
tie the bag on tight and leave it until the 
time of ripe seed. A little peep-hole may 
then be cut in the top and the pod can be 
watched every few days until it is seen to 
open and disclose the brown seeds within. 
For labels I use the little cardboard 
“ string tags.” They usually remain legible 
through the summer rains if the writing is 
done with a good black pencil. 
The process of doubling in a flower is 
considered to be really a transformation of 
the other parts into petals. First the 
stamens are transformed, and finally the 
alteration may even extend to the carpels. 
In such cases it is often impossible either to 
get pollen from a bloom or to effect fertiliza- 
tion on it. Sometimes, however, when trans- 
formation has been almost complete so far 
as the stamens are concerned, a few petals 
may be found towards the centre of the 
flower, possessing thick yellow edges. If 
these thickenings are split open with a small 
knife blade or a pin, pollen will be found 
inside — not much, but enough to work with. 
Different sorts show great variations as 
seed producers ; some which apparently 
possess seed pods rarely if ever produce 
seeds. Duchesse de Nemours (Calot) is one 
of these. I have crossed on it several times 
and have never got anything. In some 
blooms it is almost or quite impossible to 
find any stigmas on which to place pollen. 
Richardson’s Grandiflora is a flower where 
the process of transformation seems to have 
sacrificed everything to the production of 
petals ; and so with many others. I have 
never been able to do anything with Therese ; 
but Mr. Ringle, of Wausau, Wis., reported 
some time ago having got a few seeds from 
it after repeated trials. 
There are some varieties on the other 
hand that are conspicuously good seed bear- 
ers. One of these is Primevere. I think I 
have never found any pollen on it, but I use 
it every year as female parent and it sets 
such grand pods of seed that the stems have 
to be staked to keep them from being broken 
by the weight of the seed. I mentioned in 
Bulletin No. 5, a bloom of Primevere from 
which I had taken 61 good seeds. 
Other good female parents are Venus and 
Marie Crousse, neither of which ever show 
pollen of their own. James Kelway, M. Mar- 
tin Cahuzac, Adolphe Rousseau, are also good 
seed producers, but they all have stamens, 
and should be carefully examined before be- 
ing used. The Japanese blooms almost al- 
ways set seed well; and though it is very 
unusual to find any free pollen on them, 
some may almost always be had by opening up 
the thickened edges of the central petaloids. 
A curious case is that of the Wittmanniana 
hybrid, Le Printemps. It happens to be the 
only one of these hybrids in my garden of 
which I have large and robust plants. It is 
a single, with stamens and carpels apparently 
well developed. Yet in spite of repeated 
efforts through several years, I have never 
had a fertile cross either on the plant itself 
with other pollen or on any other sort where 
the pollen of Le Printemps was used. It is, I 
suppose, a sterile hybrid. 
Generally speaking the singles yield large 
quantities of seed. Most of them came 
themselves out of double strains, and from 
their seed there comes a large percentage of 
double progeny. Hence they ought to prove 
pretty satisfactory as seed parents for crosses. 
Last year I had a strange disappointment 
in connection with P. lutea as female parent. 
I had made some crosses on this species 
using pollen from Chinese Peonies, and was 
rewarded with half a dozen immense pods 
of seed. When the pods burst, there they 
were, two or three dozen big black glossy 
seeds. But when I got them out, I noticed 
that they gave a little under pressure be- 
tween the fingers, and on breaking one open, 
I found that the seed was nothing but a 
tough shell, there was nothing inside. And 
so it proved with all of them. Now gener- 
ally speaking, when a cross fails the seed 
pod soon shrivels and dries up, but these had 
all the appearance of the most successful 
crosses. What sort or degree of fertilization 
was brought about here that would produce 
big seed pods, and fine looking seeds, yet all 
only a hollow pretense ? 
I have spoken of several little implements 
that the hybridizer needs, and now for the 
sake of those who do not live in large cities, 
I shall tell where these things may be had. 
Magnifying glass. Get what is called a 
doublet magnifier, giving 14 diameters mag- 
nification. They cost about $1.25 to $1.50, 
and may be had from the Kny Scheerer Co., 
404 West 27th St., New York, from the Scien- 
tific Materials Co., Pittsburg, Penn., or from 
any scientific supply house. In using, the 
glass must be placed very close to the object 
and the eye almost touching the glass. 
Pincers. I like what are called Denton 
Forceps, but any small sized pincers will do. 
Carried in most drug stores. The Denton 
Forceps may be had from the Kny Scheerer 
Co., for about 50 cents. 
Petri Dishes or Watch Crystals (watch 
glasses) may be had from either of the above 
firms. Petri Dishes, 2 inch, about 20 cents 
each ~ watch glasses cheaper. 
Small Sable Brush, at any art store. 
Tags for Labeling. I use Dennison Marki 
ing Tags 36 B. They are of good size. 
