OBSERVATIONS FOR YOUNG BOTANISTS 131 
eight on two fingers, not round and round. We thus see how 
plants have to obey mechanical laws as well as we ! 
Insectivorous Plants. — Our commonest sundew [Drosera 
rotundifoUa) is often found among bog- moss in morasses, so that 
most students may have the opportunity of examining it. Its 
little green, round blades are covered with stiff bristle-like pro- 
cesses called “ tentacles,” terminated by a gland which secretes 
a drop of gum, looking like dew, whence its name. A few plants 
in moss should be put into a soup-plate of water. Then place 
a tiny fragment of hard-boiled white of egg, gently laid upon the 
short tentacles in the middle of the leat-blade. It should be 
e.xamined from time to time. It will be seen that the longer 
marginal tentacles bend over it, although they had not touched 
it, and bring their glands down upon the food. The glands now 
pour out a digestive fluid, dissolving the white of egg, which 
gradually becomes semi-transparent till it is all gone. While 
this is going on the naturally uniformly pink-coloured tentacles 
become much paler in tint. This means that the “ nitrogenous ” 
food is being conveyed down the tentacles into the leaf. After 
a time, the tentacles rise up and spread themselves outwards 
as they were at first, while they regain their colour, from below 
upwards, and are then ready for a fresh meal. Indigestible sub- 
stances, such as hard cheese, potted meat, or the hard skin of 
an insect are either rejected or else they kill the tentacles. 
The butterwort [Pingiiicula vulgaris) is very common in moist 
places in the west ot England. It has a rosette of pale yellow- 
green spoon-shaped leaves. These are covered with stalked 
glands visible through a lens ; and if a piece of egg be placed 
on the leaf the margins soon roll over it so as to place the 
marginal glands on it. They then pour out a digestive fluid as 
before in the case of the sun-dew. The chief use of this peculiar 
habit of eating animal food is to enhance the fruiting and seed- 
ing, as experiments show that many more seeds are produced 
if the sun-dew plants be fed, than if they are not so treated. 
Propagation. — All parts of plants are capable of reproducing 
the plant, though flowers and fruits are, of course, the principal 
means. Leaves form no exception, and advantage is taken by 
florists of this means of multiplying certain plants, such as 
begonias and gloxinias, by cutting up a leaf, as each of its 
pieces will strike root and then throw up a bud. 
Some plants, however, habitually produce buds on leaves. 
There is a fern, commonly grown in conservatories, the fronds 
of which are covered with little buds which can be detached 
and grown. A peculiar water-lily alw'ays carries a bud at the 
top of the leaf-stalk at the notch in the blade ; while a fleshy- 
leaved plant of Madeira [Bryophylluin) sheds its leaves while still 
green. They fall on the ground and strike root at every notch, 
and then a bud springs up at the same place ; and so one leaf 
may give rise to half-a-dozen little plants. Our own cuckoo- 
flower (Cardamine pratensis) often has its leaves flat on the ground, 
and in moist places these will strike root. 
