Davy held up and waved a large stem of very coarse grass.
"It's an Endogen," he said, very decidedly, "isn't it, Papa?"
"It isn't at all, is it, Papa?" eagerly asked little Prue.
The Chief Gardener took the plumey stem and sat down.
"Why do you think it is an Endogen, Davy?" he asked.
"Because it's a grass, and belongs to the grass family. And corn belongs to the grass family, too, and corn is an Endogen, for it has a big pith instead of rings. So if corn is an Endogen, grass is, too."
The Chief Gardener smiled.
"Well, that's pretty good, Davy, and is true enough, but it isn't just the best way to reason. Now, Prue, why did you think it was an Exogen?"
"Because the stem is hollow, and makes a ring when you cut off a little slice of it, and because the bloom part is in five pieces."