November 9, 1907. 
THE GARDENING WORLD. 
7 i 5 
Althaea pontica. 
[Maclaren and Sons. 
The Pontic op Turkey Hollyhock 
lAlthaea pontica). 
. . SOME . . 
Sensitive Plants. 
No doubt many people have at various 
imes noticed the habit of some plants of 
dosing their leaves and flowers. Natur- 
illy we often wonder at these things, but 
vhen we look into the causes which go to 
)ring about such regular movements we 
jet more interested in the subject. 
Among some of our common wild plants 
nany have doubtless noticed the Scarlet 
ifimpernel (Anagallis arvensis) which has 
1 very sensitive nature. This little 
lowering plant has been often called the 
shepherd’s Weather Glass, so true are its 
brecasts of the weather. If it is going to 
se wet or should it be cloudy, the flowers 
.vill be found closed. If it is to be fine, 
hey will have their petals expanded fully. 
Some flowers close regularly at sunset 
md open again at sunrise. The Oxalis 
:ribe are very prominent examples of this, 
[f we notice the Wild \\ ood Sorrel 
(Oxalis Acetosella) we shall observe its 
dover-like leaflets opening wide in the 
morning at 6.45 and at 5.30 in the evening 
[hey will commence to close. This is one 
of the best plants for those desiring to 
watch this movement of the leaves. It 
can easily be grown in a small flower pot 
as a window plant, and would not only be 
interesting, but of some decorative value. 
Another plant which is not only sensi¬ 
tive to the wind, but even to a gentle 
touch, is one belonging to the Acacia tribe 
(Mimosa pudica). This plant, which can 
be grown in the window, is most remark¬ 
able ; it will, at the least touch, lower its 
leaves and close up its leaflets. If the 
sunlight is too strong it will have the 
same effect. The amateur gardener 
would do well to have it amongst his col- 
.ection of greenhouse plants; it will well 
repay cultivation, and can easily be ob- 
:ained from any nurseryman. 
The Calvary Clover (Medicago Echinus), 
with its blood spots marked on the leaves, 
is very pretty and opens its leaves in the 
morning, closing them in the evening. 
Almost all Acacias and plants of the 
Oxalis genus exhibit similar movements. 
The common Chickweed (Stellaria media) 
becomes affected as night approaches, and 
its leaves rise upwards with their faces to¬ 
wards each other-, thus enclosing and pro¬ 
tecting the growing point. 
To find an explanation of the sensi¬ 
bility of plants we must carefully study 
the conditions of growth, temperature, 
and natural habits. We shall thus gain 
knowledge which should prove extremely 
useful and interesting. From the physio¬ 
logical pointy of view, the movements of 
the leaves are due to the action of light, 
for when the light begins to get weak it 
takes the power from the sensitive plant. 
Naturally speaking, all plants are more 
or less sensitive, as they are governed by 
the action of various forces, heat, light, 
air, etc. In cases of climbing plants, 
these are sensitive to things with which 
.they come into contact. These things, 
.therefore, will explain why plants are sen¬ 
sitive, and should cause the reader to ad¬ 
mit that there is much that is worthy of 
(closest observation in sensitive plants. 
Albert R, Gould. 
Within recent years many flower lovers 
have gone back to the single Hollyhock 
raised from seeds in order to escape from 
the dreaded Hollyhock disease. As a rule 
these seedlings consist of varieties of the 
common Hollyhock with occasionally a 
few yellow ones derived from A. ficifolia. 
There are, however, other species of 
Hollyhock, some of them not, perhaps, so 
good as the common one, but others 
equally so or even better. 
The accompanying illustration shows a 
large plant of a Hollyhock which has 
been introduced from Turkey and grown 
in the Royal Gardens, Kew. The leaves 
are broad, shallowly seven lobed, and as 
a rule keep healthy right dowji to the 
ground. Plants raised from seeds give 
rise to slight variations in colour, but in 
all cases the blooms are of large size and 
usually of some shade of rose, dark or 
light, with a yellowish centre. This 
yellow hue shows up dark in the centre of 
the blooms, but some of the flowers have 
a dark red zone surrounding the yellow 
one. Variations of this character should 
be seized upon by growers for the purpose 
of getting crosses with even larger flowers 
more varied in colour on a plant of vigor¬ 
ous constitution. The clump from which 
the photograph was taken stood 10 ft. high 
at least, and was the most conspicuous of 
all the Hollyhocks during the period of 
blooming. 
