"It tells all about it in my book here--'Gray's Botany for Young
People.' But I can tell you what use it is to _us_," continued Thorny,
crossing his legs in the air and preparing to argue the matter,
comfortably lying flat on his back. "_We_ are a Scientific Exploration
Society, and we must keep an account of all the plants, animals,
minerals and so on, as we come across them. Then suppose we get lost
and have to hunt for food, how are we to know what is safe and what
isn't? Come, now, do you know the difference between a toad-stool and a
mushroom?"

"No, I don't."

"Then I'll teach you some day. There is sweet flag and poisonous flag,
and all sorts of berries and things, and you'd better look out when you
are in the woods or you'll touch ivy and dogwood, and have a horrid
time if you don't know your botany."

"Thorny learned much of his by sad experience and you will be wise to
take his advice," said Miss Celia, recalling her brother's various
mishaps before the new fancy came on.

"Didn't I have a time of it, though, when I had to go round for a week
with plantain leaves and cream stuck all over my face! Just picked some
pretty red dogwood, Ben, and then I was a regular guy, with a face like
a lobster and my eyes swelled out of sight. Come along and learn right
away, and never get into scrapes like most fellows."

Impressed by this warning, and attracted by Thorny's enthusiasm, Ben
cast himself down upon the blanket, and for an hour the two heads