“The buds,” said Frank, putting down his lens, “are in pairs; and the stem is swollen where each pair of buds comes off.”
“Very good,” said Uncle George. “That is exactly what I wanted you to notice. The swollen parts of a stem are called its nodes. In every stem, buds and leaves occur at the nodes. Nodes are very well seen in grass and corn stems.”
“Then at the top of the twig there is a very large bud and a pair of small buds, one on each side of it,” said Frank.
“You have described it very well,” said his uncle. “Now, Tom, what about the willow twig?”
“I see some very tiny marks on it,” said Tom. “There are no rings marking the year’s growth; and the buds are not arranged in pairs.”
Horse-Chestnut Twig, showing Three Years’ Growth.
“That is quite right, Tom. Willow grows very quickly. Your twig is all one season’s growth. It is smooth and green—not brown like the horse-chestnut twig. The buds are arranged alternately. That is to say, there is only one bud at each node.”
“Now, let us see what the horse-chestnut twig is made of.”
Uncle George next cut two pieces off the top part of the horse-chestnut twig and handed one to each of the boys.