"What are the characteristics of the framework?"
"It has big bones and little ones," cried Della.
"Good for Delila! The big bones are called ribs and the fine ones are called veins. Now, will you please all hold up your leaves so we can all see each other's. What is the difference in the veining between Ethel Brown's oak leaf and Ethel Blue's lily of the valley leaf?"
After an instant's inspection Ethel Blue said, "The ribs and veins on my leaf all run the same way, and in the oak leaf they run every which way."
"Right," approved Helen again. "The lily of the valley leaf is parallel-veined and the oak leaf is net-veined. Can each one of you decide what your own leaf is?"
"I have a blade of grass; it's parallel veined," Roger determined. All the others had net veined specimens, but they remembered that iris and flag and corn and bear-grass—yucca—all were parallel.
"Yours are nearly all netted because there are more net-veined leaves than the other kind," Helen told them. "Now, there are two kinds of parallel veining and two kinds of net veining," she went on. "All the parallel veins that you've spoken of are like Ethel Blue's lily of the valley leaf—the ribs run from the stem to the tip—but there's another kind of parallel veining that you see in the pickerel weed that's growing down there in the brook; in that the veins run parallel from a strong midrib to the edge of the leaf."
James made a rush down to the brook and came back with a leaf of the pickerel weed and they handed it about and compared it with the lily of the valley leaf.
"Look at Ethel Brown's oak leaf," Helen continued. "Do you see it has a big midrib and the other veins run out from it 'every which way' as Ethel Blue said, making a net? Doesn't it remind you of a feather?"