393 
AMERICAN AGRICULTURIST. 
[August, 
ond flower to the third flower, and so on. 
Cypripedium, or Lady’s Slipper,(flg. 2) although 
of the Orchid family, and equally dependent up¬ 
on insect aid, gets its work done by a different 
class of insects and in a different way. The 
front petal, to which the honey-tube in Orchis 
belongs, here forms the great sac or slipper, and 
is the only showy part, the other leaves of the 
flower being dull greenish, or purplish. The 
slipper, which in shape might suit the taste of a 
Chinese lady, is open at the instep; and there 
the edges are rolled in, after the fashion of the 
entrance to a rat-trap. The central 
part of the blossom, which curves 
downward and is partly thrust into 
the slipper, consists of stamens, style, 
and stigma. The spade-shaped, petal¬ 
like body which covers the stigma, 
and is neatly all that is seen from the 
front, takes the place of a stamen, but 
has no pollen; underneath it is the 
broad stigma, which faces to the heel 
of the slipper, as is best seen in the 
pai tly sectional view, fig. 3, and in 
fig. 4; and just back of the stigma 
are the two anthers, one on each side. 
The back, or as we may say the sole, 
of the slipper, is lined with long hairs 
or soft bristles, and these appear to 
contain something attractive to in¬ 
sects. There is no honey in the slip¬ 
per. The anthers are so placed that 
the pollen can never of itself fall on 
the stigma, nor be thrown upon it by 
the wind. Indeed, the pollen does 
not fall of itself; for, although of 
tlie appearance of a damp powder, or 
so moist in the yellow species as to 
be almost pulpy, the surface is cover¬ 
ed with a thin film of sticky var¬ 
nish. When touched with the finger, 
the varnish adheres, and brings away 
with it a layer of the pollen, of the 
size of the adhering surface. 
Now, as to the fertilization. The 
flower left alone would be hopeless¬ 
ly sterile. Although we have never 
seen an insect spontaneously enter the 
slipper and do the work, we are about 
as sure that the work is done in this 
way, as if we had seen it. Probably 
it is visited by nocturnal insects. The 
slipper may be entered by the orifice 
in front, which, in most species, of¬ 
fers the readiest access; or, from be¬ 
hind, by crawling under either anther, 
and thence under the stigma into the 
main sac. A large fly, or a coleop¬ 
terous insect of corresponding size, 
entering from behind, woukl probably 
hit the back of his head or eye against 
one of the anthers, and as he crept 
under the stigma, might lodge some 
of it there. Feeding upon the hairs as he 
passed on, the fi-ont orifice ■would be before him 
for egress; but its incurved border would inter¬ 
pose some obstacle. It offers none to entrance; 
and we presume that the insect enters at the 
front, and passing onwards, departs by the 
back door. In so doing, whether he turns to 
the right or the left, he must rub his head 
against an overhanging anther, and carry ofiT a 
plaster of pollen. If he then passes to anoth¬ 
er flower of the same species, and enters it by 
the front orifice, as he proceeds towards the 
most practicable exit he must crowd under the 
stigma, upon which he will hardly fail to depos¬ 
it some of the pollen brought from the neigh¬ 
boring flower. Now, that this is really the way 
of it, that it is intended the insect shall enter 
at the instep and emerge at the heel of the slip¬ 
per, and so bring the pollen of one flower to 
the stigma of another—is as good as demon¬ 
strated by the peculiar character of the surface 
of the stigma in this flower. It is not glutinous 
as in other Orchids, but only moist, and is rough 
to the touch. Under a magnifying-glass the 
roughness is seen to arise from the whole sur¬ 
face of the stigma being covered by sharp pro¬ 
jecting points, or what would be rigid bristles 
TR'EE HOUSE LEEK.— {Sempervivum arhoreum.) 
if they were longer; and these all turn forwards, 
so that the apparatus may be likened to a rasp, 
or to a hand wool-card of the olden time; and 
one cannot resist the conclusion that it is intend¬ 
ed to card off and to retain the pollen brought 
upon the head of an insect entering at the 
front, and on its way to get out at the back 
part of the flower.—A more ingenious and effec¬ 
tual contrivance for crossing the flowers of a 
species by the help of insects, could hardly 
be devised. A. G. 
---—-- 
The LiNNiEAN Society of Lancaster, (Pa.,) 
City and County. We have received an essay 
by S. S. Rathvon, Esq., which was read at the 
last anniversary of the society, and which sets 
forth its objects and progress. We notice this to 
give the Society our best wishes for its success, as 
well as to call attention to the utility of such in¬ 
stitutions. Natural History Societies and Clubs 
are springing up all over England, an old coun¬ 
try, which one would suppose had been so thor¬ 
oughly explored, that there remained little to re- 
w^ard the naturalist. Yet this is not the case, 
for industrious 'U'orkers are constantly develop¬ 
ing there some new facts of interest. In a new 
country, like our own, there is greater induce¬ 
ment to the student, and there should 
be in every considerable village or 
town a museum of its natural pro¬ 
ductions of all kinds. These local 
collections have an interest to the 
commuity in which they are made, 
and are of great value to science, as 
they not only furnish important data 
upon the distribution of plants, ani¬ 
mals, etc., but they preserve speci¬ 
mens of many things that are rapid¬ 
ly disappearing as the population be- 
' comes more dense. Such collections 
always increase with astonishing rapi¬ 
dity where a nucleus is once formed, 
and their ntility in giving direction to 
the tastes of the young is incalculable. 
House-Leeks and Stone-Crops. 
There are some plants so very com¬ 
mon that their beauty is unappreciat¬ 
ed. The well known House-leek is 
one of these, and to us who like 
plants, even if they have not flow¬ 
ers upon them, this much neglected 
and even persecuted individual is a 
great favorite. The healthy green of 
its leaves, their symmetrical arrange¬ 
ment in beautiful rosettes, its tenacity 
of life, growing where scarcely any 
thing else will live, defying frost and 
drouth, but bright and cheerful under 
the most adverse circumstances, are 
qualities that commend it. To be 
sure it seldom flowers, but then its 
clusters of leaves are handsome 
enough to answer for flowers; they are 
much like green camellias. The bo¬ 
tanical name is Sempervivum tectoi'um. 
Sempervivum means “ always living,” 
or “ live-forever.” The specific name 
tectorum, is from the Latin for roof, in 
allusion to its growing upon houses; 
an I our common name, House-leek, 
refers to the same thing. It is an 
exceedingly useful plant for Rock 
work.—Another favorite of ours is a 
very old green-house species, Semper¬ 
vivum arboreum, which we now rare¬ 
ly see, it having been cro-u'ded aside 
by novelties that are often inferior to it. 
We were so much pleased to see a fine en- 
gratung of our old friend in the London Gar- 
denei-’s Magazine that 'we have reproduced it. 
The plant is of the easiest culture, and when 
well grown, makes a fine sho'U'. It needs to be 
kept in the house in winter. We have found to’ 
our sorrow that mice are very fond of thiS’ 
plant, seeming to prefer it to all others. There' 
are several varieties, one with purple leaves^ 
one in which the leaves are edged ■ndtli red, and 
.another in which they are beautifully striped 
tvith yellowish white. The whole family (Cras- 
sulaceae) to which these plants belong, is de^^ 
serving more attention than it now hast 
