The girl was staring up at him in astonishment.  And Gavin was aware for the first time that he had been thinking aloud.

“You see,” he expounded. smiling vaingloriously down at her.  “I amused myself at the Miami library Saturday by browsing over a sheaf of Government plant reports.  And those two solid facts stuck in my memory.  Now. won’t I be an invaluable aide to your brother if I can remember everything else as easily?”

Still puzzled she continued to look up at him.

“It’s queer that a man who has just come down here should remember such a technical thing,” said she.  “And yesterday you warned me against letting Bobby Burns wander in the palmetto scrub, for fear of rattlesnakes.  I—­”

“That deep mystery is also easy to solve,” he said.  “In the smoker on the way South several men were telling how they had lost valuable hunting dogs. hereabouts from rattlesnakes.  I like Bobby Burns.  So I passed along the warning.  What are those queer trees?” he asked shifting the dangerous subject.  “I mean the ones that look like a mixture of horse-chestnut and—­”

“Avocadoes,” she answered, interest in the task of farm guide making her forget her momentary bewilderment at his scraps of local knowledge.  “They’re one of our best crops.  Sometimes a single avocado will sell in open market here for as much as forty cents.  There’s money in them, nearly always.  Good money.  And the spoiled ones are great for the pigs.  Then the Northern market for them—­”

“Avocadoes ?” he repeated curiously.  “There!  Now you see how much I know about Florida.  From this distance. their fruits look to me exactly like alligator pears or—­”

Again. her laugh interrupted him.

“If only you’d happened to look in one or two more government reports at the library,” she teased. “you’d know that an avocado and an alligator pear are the same thing.”

“Anyhow,” he boasted. picking up a gold-red fruit at the edge of a smaller grove. they were passing. “anyhow.  I know what this is, without being told.  I’ve seen them a hundred times in the New York markets.  This is a tangerine.”

“In that statement,” she made judicial reply. “you’ve made only two mistakes.  You’re improving.  In the first place, that isn’t a tangerine, though it looks like one—­or would if it were half as large.  That’s a king orange.  In the second place, you’ve hardly ever seen them in any New York market.  They don’t transport as well as some other varieties.  And very few of them go North.  Northerners don’t know them.  And they miss a lot.  For the king is the most delicious orange in the world.  And it’s the trickiest and hardest for us to raise.  See, the skin comes off it as easily as off of a tangerine, and it breaks apart in the same way.  The rust mite has gotten at this one.  See that russet patch on one side of it?  You’ll often see it on oranges that go North.  Sometimes they’re russet all over.  That means the rust mite has dried the oil in the skin and made the skin thinner and more brittle.  It doesn’t seem to injure the taste.  But it—­”