Part 5

Is that all the work they do?

Sometimes these fibres reject things not wanted in the tree, and that often prove poisonous to its growth. Such important little workmen as the spongioles ought not to be disturbed in their labour, and this is what makes the difficulty in moving trees.

I know that most of those I move are sure to die. But gardeners are more lucky.

The reason is, because they do it at a proper time.

What, father, can we catch the spongioles asleep?

Not exactly; but they only live a year, and you must take up the tree between the time of the death of one set, and the production of another, which is the winter season. Even then you should get up as many fine roots as possible, for at the end of these the spongioles grow.

All roots are not alike, father.

That is true: some are creeping, or fibrous, or bulbous, or knobbed, or taprooted. Can you give me instances of each?

Let me see. The mint spreads underground by its creeping roots. The potatoe is knobbed, and the onion and tulip are bulbous. The grass is fibrous, and the parsnip has a tap root.”

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So much for the root. Now let us look at the bark. I suppose you have noticed the difference of the bark of our forest trees.

I know that they shed their bark, though not in the same way. The stringy bark peels off in strings. The gum throws out fine long ribands, waving in the wind. The iron bark sheds its thick coat in great lumps.

But does the whole of the bark thus fall off?

Oh, no: it is only the rough, worn-out stuff. There is always bark left. It puts me in mind of my hand, that got so horny after sawing a whole day at a big tree; for days after the rough skin got peeling off as if it was not wanted.

Then you have more skins than one. You are just like a tree, for that has several coats to its bark. Which is the softer, the outer or inner bark?

The outer is hard, and the inner soft. But there is a fresh gum tree just cut down: that will show us the barks.--Yes, now I peel off the outside, there is a very soft, juicy stuff, a thing I feel--a soft coat of bark close to the ring of white-looking wood.

Mind, Willie, the outside is the cuticle or epidermis, having pores or openings through which moisture issues at one time, and is absorbed at another. These Stomates or openings are very small; in our Bush Pigfaces, that the Blacks eat, there are 70,000 Stomates to every square inch of skin.

Then the tree perspires in the same manner that we do: that is odd. But what is the middle pulpy bark, with its green colour and sticky feeling?

Botanists call that the Chlorophyll or colouring matter. The inner bark is the liber, which you see to be soft and fibrous like, being full of sap.

Why, this is something like our skin, as there is a watery stuff between our cuticle and the skin that has the blood in it. I have heard of people writing on bark: that must have been on the liber.

It was so. The English wrote on the bok or bark, and thus we have the word book; while with liber we connect the word library. But we shall return to the liber in another lesson.

Is the cuticle always naked?

No, some plants I have seen with hair over the skin, and others with something like scales.

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Having talked of the bark, boy, we will turn to the stem. What are your notions about it?

My eyes and fingers tell me that, after I pass the liber of the bark, I reach the fresh-looking white ring of wood, and that after that the wood which is still in rings gets harder and drier toward the centre. But I thought there was pith in the middle of a tree: how is it there is none seen here?

Because these woody layers or rings have crushed it in time. I must say a little about this pith. You know it is soft enough; that is, because it is composed of small cells filled with juices at first, and then with air.

Cells, father! what, like the bees’ honey-comb!