HOW PLANTS SPREAD AND MULTIPLY 37 
they fall off, and are then carried along ditches by the 
autumn rains to found fresh generations. 
A very pretty sight is seen on a common greenhouse 
fern, where the young plant is to be found upon the 
fronds, a complete miniature of its parent, with its own 
little fronds unfolded. After a time these too drop off 
into the soil beneath. A similar arrangement may be 
found in one of the houseleeks, the fat-leaved rosettes 
of which you must have often seen on the roofs of old 
houses. From the base of one of these leaves will come 
a fine thread, and at its end a round ball of leaves, 
which continues to grow until the filament snaps and the 
ball rolls off in the wind. 
Seaweeds are spread very largely in this way. A 
storm comes on, and great shreds are torn away from 
the masses that cling to rocks, and the current carries 
them off to fresh positions. A scrap is caught on a 
rock, and, being of low organisation, is able to go on 
comfortably in its mutilated condition until it can renew 
its lost parts. 
By using this principle of “vegetative reproduction ” 
gardeners grow plants from cuttings, taking just one part 
of the plant, putting it in the ground, and allowing it to 
build up the other parts for itself. With Begonias one 
leaf is actually sufficient! This marks a great differ- 
ence between the highest plants and the highest animals. 
You might feed a cat’s leg with the most suitable food 
for a very long time before you could grow a new cat, 
and even if you had the rest of the cat the best nursing 
in the world would never enable it to grow a new leg. 
But almost any large part of a plant, if carefully treated, 
will reproduce the whole. All the various ways of grow- 
ing plants from cuttings or by grafts depend upon this 
