1872.] 
AMERICAN AGRICULTURIST. 
4,61 
nearly all Zonal Geraniums; one half the florets 
faded before the other half came out. In the 
■window each cluster would keep about three 
weeks; if one floret dropped, another came out 
in its place, or the rest pressed together and 
filled up the gap. Cuttings from these did 
equally well last winter. They stood on the 
window-sill, close to the glass. The room had 
only a wood-fire, and was never very hot—» 
which last item, by the way, is a very import¬ 
ant one for your own health as well as for that 
of your plants. Don’t let the thermometer get 
above 65 or 70° at the most, going down not 
lower than 45° at night if possible. You can 
easily accustom yourself to the temperature, 
and will be all the better for it. 
Providence, R. I. G. H. B. 
Seedling 1 Pelargoniums. 
BY JEAN SISLEY, OP LYONS, PRANCE. 
Mr. Sisley, well known as the originator of 
several choice varieties of double Zonale Pelar¬ 
goniums, writes to the editor as follows : 
Lyons, 16th October, 1872. 
Editor of American Agriculturist, New York : 
You have asked me how I proceeded to obtain 
the new double-flowered Zonale Pelargoniums, 
and since then I have received many applica¬ 
tions for information from Belgian, English, and 
French horticulturists, particularly since my 
friend Carri&re, speaking of my double White 
Zonale in the Revue Horticole of 1st October, says 
that it is the result of scientific combinations. 
I must decline to accept this encomium, but am 
very willing to let the horticultural world know 
my very simple practice, which I have never 
kept secret. It is not necessary to discuss here 
the process of artificial impregnation; one 
familiar with horticulture knows how it is prac¬ 
ticed. I will therefore at once inform your 
readers of my proceedings. 
When, six years ago, I began the artificial 
impregnation of Zonale Pelargoniums, I first 
procured about fifty of the best varieties of sin¬ 
gle-flowered Zonale Pelargoniums, selected from 
the various colorings, and about two hundred 
plants of the then existing double-flowered 
varieties. And until 18701 continued to buy all 
the new double varieties that were brought out, 
and all the single-flowered varieties which were 
of different shades from those in my collection. 
Without any preconceived theory I impreg¬ 
nated all the single-flowered with the pollen of 
the double ones which had stamens. 
For three years I did not obtain a seedling 
worth mentioning, and I was on the eve of 
giving up artificial fecundation, when in 1869 I 
obtained Victoire de Lyon and Clemence Royer, 
which, although not perfect in form, were very 
different in color from any double Zonale Pelar¬ 
gonium until then produced. This led me to 
continue my efforts. Since the first year I had 
kept my seedlings that were alike in shape and 
color to those in my collection, and rejected the 
old ones. I proceeded in the same way with 
the double-flowered, and rejected principally all 
those that had few or no stamens as useless to 
me. I had been led to this selection by the idea 
that single flowers obtained from single flowers 
impregnated by double ones, might 'perhaps be 
more disposed to produce double flowers than 
the old sorts. 
This selection is the only scientific combina¬ 
tion I have used, and although I can not affirm 
that this proceeding is the cause of my success, 
I recommend this method to those who may be 
disposed to practice artificial fecundation with 
other species of plants. Nevertheless I have 
not learned by my practice anything that can 
be called a theory, because among my seedlings 
coming from the same mother and the same 
father I have found them all differing from one 
another. My double White is the produce of 
a single White (one of my seedlings second or 
third generation) by a double Red; but four 
other seedlings from the same fecundation are 
either white, pink, or red, and all single flowers. 
And there is nothing astonishing in this. Why 
should the laws of nature vary and act differ¬ 
ently in the vegetable world from what they do 
in the animal world ? Nature and science have 
not yet taught us why the offsprings of the same 
father and the same mother are always different 
from one another, notwithstanding their family 
likeness. And it is very likely that man will 
always be ignorant of this and many other laws 
of nature. The only thing I know, and every 
horticulturist knows, is that to obtain double 
flowers, single flowers must be impregnated by 
double ones. 
Measuring the Hight of Trees. 
It is often desirable to determine the hight of 
a tree, if not with mathematical correctness, 
with something approaching to accuracy. 
There are instruments made for the purpose of 
measuring with great precision, but there are 
several methods by which the hight can be 
ascertained without expensive appliances. By 
measuring the shadow of a rod or other object 
of a known length and the shadow of the tree, 
a simple sum will give the hight. Suppose that 
we measure the shadow of a perpendicular rod 
six feet long, or that of a man of the same 
hight, and find it to measure eight feet, and then 
measure the shadow of the tree and find it to 
be 132 feet; then 
as 8 ft. : 6 ft. : : 132 ft. : 99 ft. 
The Gardeners’ Chronicle figures a simple 
quadrant for tree-measuring which we here re¬ 
produce. A quarter of a circle is made of some 
light wood, and a small plumb-bob is suspended 
from what would be the center of the circle, 
and a mark made just half-way of the curved 
side of the quadrant. Two small eyes for 
sights attached to one of the straight edges 
make the implement complete. The quadrant 
is held as in the diagram, the operator moving 
backward or forwards until he can see the top 
of the tree through both sights, the plumb-line 
at the same time hanging over the mark. The 
distance of the observer from the tree, when he 
can see the top of it in this manner, will be the 
hight of the tree. Allowance must be made 
for the hight of the eye from the ground, and 
for any difference in the level of the ground 
between the tree and the observer. 
---- 
Yuccas and Insects. 
At the last meeting of the Association “ with a 
name,” Mr. Riley stated as a discovery of Dr. 
Engelmann, that our American Yuccas could 
be fertilized only by means of some artificial 
agency, and that an insect was engaged in the 
work. This insect, a moth, was described by 
Mr. Riley as one hitherto unknown to entomol¬ 
ogists, and one by its structure well calculated 
for its work. The insect collects the pollen 
which would not otherwise reach the pistil, and 
places it upon that organ and lays her eggs. 
The young larva after hatching eats its way 
into the developing fruit, lives on the maturing 
Yucca seeds, and- by the time the seed-pod is 
ripe the full-grown larva leaves the capsule and 
enters the ground, where it undergoes its trans¬ 
formation, and comes out the following spring 
as a moth to repeat the work. Mr. Riley is 
quoted as saying, “In the more northern por¬ 
tions of the United States and in Europe where 
Yuccas have been introduced and are cultivated 
for their show}' 1 blossoms, the insect does not 
exist, and consequently the Yuccas never pro¬ 
duce seed there,” and suggests that the insect be 
; captured in the chrysalis state and sent to 
j those countries where it is lacking. Three 
j large plants of the Adam’s-Needle, or Bear- 
grass ( Yucca filamentosa), in our garden near 
New York, produced fine clusters of cap¬ 
sules this autumn; upon examining them 
we found that apparently every seed-vessel 
either contained an insect, or had a hole 
showing where one had escaped. The cap¬ 
sule of this Yucca consists of three cells, and 
generally but one of them was inhabited by 
the larva, which destroyed the seeds in 
that, while the contents of the other two 
cells were untouched. All the capsules 
were one-sided or contorted, owing to the 
presence of the caterpillar. The fact is an 
interesting addition to our rapidly-ac¬ 
cumulating knowledge of the relations 
between plants and insects, but it is a 
question if all Yuccas require this in¬ 
sect aid in order that they may pro¬ 
duce seed, or that it is always neces¬ 
sary, even with our commonest species, Yuc¬ 
ca filamentosa. A very observing friend who 
made extensive experiments with seedling 
Yuccas in the hope of obtaining some new 
varieties, is quite sure that he has obtained 
crops of seed without any of the distortion of 
the capsule to which we have referred. A re¬ 
cent Gardener’s Chronicle, alluding to the state¬ 
ment that Yuccas do not fruit in Europe, cites 
two cases in which Y. filamentosa produced 
seeds, which would show either that the moth 
in question is in Europe, that some other insect 
does the same work, or that the presence of an 
insect is not always required. During a recent 
visit to Georgia we found Yucca gloriosa in fruit. 
The fruit of Y. filamentosa is a dry capsule, 
while that of Y. gloriosa is pulpy, and when 
quite ripe is as soft as a banana. We examined 
a number of fruits of Y. gloriosa , and failed to 
find any distortion, perforation, or other indica¬ 
tion that an insect had entered or made its 
exit. We hope that those who live where this 
and other species fruit will continue the investi¬ 
gation begun by Dr. Engelmann and Mr. Riley. 
