MO]liMEXTS IX THE ORGAXS OE PLAXTS 
0 
a plant, is always for some settled purpose connected with its 
existence, and this will be very apparent as we ascend the scale 
of plant life. 
We may observe in many common plants some curious and 
varied movements in the stamens at the period of fecundation. 
In the Mulberry, the Nettle and the Pellitory, for instance, the 
filaments of the anthers are bent backwards on themselves under 
the pressure of the floral envelope, but as soon as the minute 
flowers open these filaments unroll or straighten themselves out 
and the pollen, in the form of fine dust, is projected for a distance 
of a yard or more around, due in a great measure to the simple 
elasticity of these organs. In the Rue, at the moment of fecunda- 
tion, each of the ten stamens bends over the stigma, deposits its 
pollen there and resumes its original position. A very similar 
phenomenon is exhibited by the common Nettle, and on a warm 
still day, by intently listening near a bed of nettles, the ear may 
detect the bursting of the minute pollen sacs and the eye 
observe the dust-like clouds caused by the little pollen-grains set 
free. A closely allied plant, the Wall-pellitory, common on old 
walls and ruin heaps, is very curious in its inflorescence and 
fructification. If the minute flowers be examined as soon as 
they expand, it will be found that the filaments of the anthers 
are all bent inwards, but as soon as the warmth of the sun has 
brought the pollen in the anthers to a fit condition to be dis- 
engaged from them, they instantly fly back as though by a 
spring, and discharge simultaneously their dust-like pollen. 
This motion may be induced by simply inserting a needle-point 
into the centre of one of the minute green flowers, when a mimic 
artillery discharge will take place. A common denizen of our 
stoves, known as Pilea muscosa, gets its popular name of Artillery- 
plant from precisely the same phenomena being displayed 
by it. 
Another common wall plant, Linaria cynihalaria, exhibits 
motion, but of such a slow kind as to be only studied in its 
effects. It raises its stems. Its habit is to grow from the 
fissures and crevices of old walls, and after flowering and forming 
its minute fruits, it appears to endeavour to hide them by turning 
aside, dragging them into any convenient crevice in the wall, 
and then, when fully ripe, the pods burst and the scattered seeds 
are sown in the deh'is of the decaying stone. 
A somewhat similar movement takes place in the well-known 
submerged aquatic plant, V allisnevia spiralis, the flower-stalk of 
which, bearing the female flower, twines itself tightly into a 
spiral screw and draws the flower, which previously it had borne 
on the surface of the water, down to the bottom, but not till the 
stigmas have been covered with the pollen-dust from the floating 
male flowers, these in their turn having at the critical moment 
of expanding been disengaged from their creeping stems at the 
bottom of the lake. These are all cases of unconscious movement 
for the definite object of fertilisation, might one not say of 
instinct ? 
