7. Dora was holding up one spray after another to the light. 'What are
all these pretty marks on the leaves, mother, lines crossing about all
ways?'

'Those are veins, dear. They carry the sap that feeds the leaves.'

8. 'What is sap?'

'The blood of plants and trees.'

'Oh,' said Dora, 'then that is the wet that comes out when I pick a
flower or cut a leaf!

9. 'But look at this!' and she held up one of the sprays.

At the end of it was a little bunch of white, curly roots. Each root was
not much thicker than a thread.

10. 'Don't touch them,' said the mother; 'roots are very tender things.'

'What is the good of them?' asked Dora.

'What is your mouth useful for?' asked her mother.

11. 'Oh, do you mean that the ivy eats and drinks?'

'Yes, that is what I mean. These roots take out of the water, or out of
the earth, all sorts of things good for the food of the plant. They then
send them up into the stem and on into the leaves.'