Folks, this is a side story from "Things Fall Apart." In Chapter 47 of that story ('An Unfortunate Encounter with Mushrooms'), Aragorn mistakenly eats a poisonous mushroom and while lying helpless is taken prisoner. In Chapter 48 ('Matters Come to a Head'), Legolas tells Aragorn that he'd better ask Erestor for a lesson in mushroom identification. This is that lesson.
"Aragorn," called Legolas. "Is this mushroom safe to eat?"
Aragorn scowled at the grinning Elf.
"Will you never cease teasing me for eating those mushrooms in Buckland!?" he retorted in exasperation.
"Not until you prove yourself to be a connoisseur of fungus," said Legolas cheerfully. "You haven't yet asked Erestor to give you a refresher course in mushroom identification, have you?"
Aragorn groaned.
"Oh, Legolas, I can't bear the thought of being lectured yet again by Erestor. He can be so, so—"
"Pompous?" suggested Legolas.
"The very word!" exclaimed Aragorn.
"But if you don't learn to distinguish the wholesome from the poisonous mushrooms, you will have to pass over an important food source. Would you like to perish of hunger surrounded by mushrooms because you cannot tell the good from the bad?"
"I could forage for roots," Aragorn said hopefully.
Legolas waved his hand impatiently.
"Aragorn, you know that roots require much more preparation than mushrooms. When you are pursuing Orcs, will you stop to dig up, wash, peel, soak, and grate roots?"
Aragorn sighed.
"Very well, Legolas. I will study mushrooms with Erestor."
"Excellent!"
That evening Aragorn asked Erestor if he would accompany him throughout the forests of Imladris.
"I suppose you heard about what happened in Buckland when I ingested the wrong sort of mushroom," the young Man said, shamefaced.
"Yes," said Erestor severely. "I must say that I was surprised and disappointed that you made such an error. Obviously you could not have been paying careful attention during our Natural History lessons."
Aragorn sighed and shot an exasperated glance at Legolas. "You see!" he mouthed at the Elf. Legolas pretended not to notice.
The next day, immediately after breakfast, Erestor and Aragorn set out on their excursion, and Aragorn had to admit that Erestor's knowledge of mushrooms was extensive and detailed. Again and again the elf lord pointed out subtle differences between mushrooms that looked similar, one nutritious, the other poisonous. By the end of the day, Aragorn was quite grateful for the lesson.
"Thank you, Erestor," he said as they walked back toward the Hall. "I am sure that this advice will help me immensely."
"You are quite welcome," said Erestor cheerfully. He was always glad for an opportunity to show off his erudition.
They drew near the garden.
"Ah," exclaimed Erestor, "there is a mushroom we have not seen today—and a very tasty one, too! Would you like to sample it?"
"Truly, Erestor, I do not think I could eat another bite of mushroom—or anything else, for that matter!"
"You wouldn't mind if I indulged, would you?"
"Certainly not, Erestor."
Erestor happily nibbled on the mushroom until he had finished it. Shortly thereafter, Man and Elf entered the garden, and Erestor did something extraordinary. He giggled. Aragorn looked at the elf lord in astonishment. The younger Elves giggled sometimes—certainly Legolas did so occasionally—but Aragorn had never heard any of the older elf lords giggle. And of all elf lords, Erestor was certainly one of the last whom Aragorn would have envisioned giving vent to hilarity.
Erestor giggled again, this time pointing at a horse that was grazing at the edge of the garden.
"Look! A unicorn!"
"Erestor," exclaimed Aragorn. "There is no such thing as a unicorn! That is an imaginary creature."
"It is not!" declared Erestor. "Yonder it gallops."
"Yes, that creature is real," began Aragorn.
"Ah hah!" gloated Erestor. "What did I tell you? Not imaginary at all."
"But it is a horse!" finished Aragorn.
"Foolish boy. You are incapable of telling a horse from a unicorn!"
"I can too tell a unicorn from a horse," said Aragorn indignantly. "But," he added hastily, "there are no unicorns."
"Then how is it that you can tell them apart?" asked Erestor triumphantly.
"I mean, I can tell a real horse from an imaginary unicorn."
"But that would be comparing apples and oranges," Erestor objected. "Why not compare a real horse with a real unicorn."
"Because you can't," said Aragorn desperately.
"Maybe you can't," retorted Erestor, "but I can."
"Erestor, I know that there are no unicorns!"
"How do you know?" challenged Erestor.
"Because I have never seen one!"
"Tell me, Aragorn, have you ever seen a dragon?"
"No."
"Oh ho!" crowed Erestor. "Next thing you'll be telling me there are no dragons."
"Of course, not! I mean, of course I would never tell you that there are no dragons. Dragons are real."
"But how do you know if you haven't seen one?"
"I have it on the best authority—they are in all the books."
"Unicorns are in books, too," argued Erestor.
"But those are story books, Erestor—fiction!"
"Fiction! Fiction! Tell me, Aragorn, if you read a story about the forces of good defeating the forces of evil, are you going to tell me that such a story is fiction! You can never be sure that a historian has got all his facts right, but a story like that, its truth cannot be denied. You could toss in a basilisk or a phoenix, and it would still be a true story."
Aragorn was relieved to know that Erestor at least realized that basilisks and phoenixes were imaginary, even though the Elf had asserted quite illogically that including one of these fictive creatures in a narrative would not make the story any less true.
"I will concede," said Aragorn cautiously, "that a story such as you describe will not be made any more fictive by having a basilisk or a phoenix in it."
"There's a clever boy! And now, let us return to the Hall. I am dreadfully thirsty. A glass of wine, or two or three—perhaps four—would do for me just now."
"Do you in, more like it," Aragorn thought to himself. "You already talk as if you were a Man who has lain under the tap all night. I'd best get you to Elrond as quick as ever I may!"
Aloud he said, "Erestor, I believe I heard Elrond say that he was opening up an exceptionally fine bottle of Dorwinion wine this evening—laid down the year Mithrandir first visited Rivendell, if I recall correctly."
Erestor was impressed.
"The year Mithrandir first came to Rivendell," he exulted. "That wine would be of a most excellent vintage. Let us hurry!"
Erestor set off at a dead run, scurrying past the astonished Gardener and bolting past the equally amazed Door Warden. With Aragorn hard on his heels, the elf lord burst into Elrond's private chamber without bothering to knock. Elrond was just about to enjoy a quiet glass of wine, and he froze with the glass halfway to his lips.
"Sorry, Lord Elrond," gasped Aragorn. "Erestor is not himself tonight."
"We need to toast the unicorn, Elrond," proclaimed Erestor.
"The unicorn?" said Elrond.
"Yes. The unicorn in the garden."
"There is a unicorn in the garden?" said Elrond.
"You see," said Erestor, turning to Aragorn. "Elrond has just said that there is a unicorn in the garden. Do you believe me now?"
"I meant," said Elrond hastily, "Is there a unicorn in the garden?"
"Yes," replied Erestor, beaming.
"Erestor," Aragorn cried in frustration, "Elrond has not said that there is a unicorn in the garden."
"Of course not," Erestor said blithely. "I am the one who just now told him about it. But he would know a unicorn if he saw one—unlike a certain young Man I could mention. Tell me, Elrond, what does a unicorn look like?"
"Body of a horse, with a horn projecting from its forehead," replied a bewildered Elrond.
"There now—that should convince you, my young skeptic. However could Elrond describe a unicorn if he didn't know what one looked like?"
"But he is describing an imaginary creature," cried Aragorn.
"Could have fooled me," said Erestor. "He certainly sounded confident of his facts! Reeled off that description glibly enough."
"Er, Aragorn," said Elrond, "could I have a word with you, um, on the balcony? There is, ah, a tree that I think you would very much want to have pointed out to you."
"Don't mind me," said Erestor cheerfully. "I'll just have a bit of wine while you two have your chat." Before the eyes of his astonished friends, he picked up the opened bottle of wine and began to chug it. Elrond seized Aragorn's arm and dragged him onto the balcony.
"Aragorn," he hissed, "whatever is going on? What is causing Erestor to behave in this extraordinary fashion?"
"I am not certain," whispered Aragorn, "but I think it may have been a mushroom that he ate. I did not try it, but soon after Erestor ate it, he began to talk in this peculiar manner."
Quickly Aragorn described the mushroom. When he had finished, Elrond was both chagrined and relieved.
"You are right, Aragorn: it was the mushroom. For the next twenty-four hours, Erestor is going to be unbelievably silly. This unicorn is but the first of the imaginary creatures that he will see. If we are lucky, they will all be equally harmless, and he will not become frightened and run amuck. We cannot be certain, however, so he will have to be carefully watched. Did he eat the entire mushroom?"
"Every bite."
Elrond sighed. "Pity. Fortunately, however, he will suffer no permanent harm once the effects of the mushroom wear off."
"How is it that Erestor did not recognize this mushroom for what it was?"
"It is not seen very often hereabouts. Erestor could not have been well acquainted with it and probably mistook it for a common mushroom that it does in fact resemble rather closely."
"Ah, so it is not native to Imladris."
"Actually, it is native to this region. But Elladan and Elrohir have become skilled at nosing out this particular mushroom. No sooner does the fungus sprout, than they swoop down upon it. As a result, one rarely comes across a specimen."
Aragorn was surprised at the twins' thoughtfulness and diligence.
"Really, Elrond, it is quite good of Elladan and Elrohir to work so hard at keeping Imladris free of these mushrooms!"
Elrond gave Aragorn an odd look but said nothing. They returned to Erestor, who had finished the bottle of wine and was now draining Elrond's glass.
"You needn't have hurried back," he told them. "I have been quite well entertained in your absence by Harvey here."
"Harvey?" said Elrond, keeping his voice neutral.
"Yes. I had no idea that a rabbit could be such an interesting conversational partner. Of course, generally I overlook rabbits, but Harvey is a little hard to overlook. Why, Elrond, I do believe he is as tall as you!"
"Impressive," murmured Elrond.
"Yes, I thought so," agreed Erestor.
"Aragorn," suggested Elrond, "why don't you show Harvey to the garden—rabbits are fond of gardens, are they not, Erestor—while Erestor and I go down to the wine cellar to retrieve another bottle of Dorwinion."
"Capital idea!" exclaimed Erestor. He enthusiastically seized Elrond by the elbow and dragged him from the room. Aragorn stood irresolute for a moment, and then shrugged and wandered into the garden.
"Harvey or no Harvey," he muttered to himself, "'tis a pleasant place to while away an hour or two."
Sometime during the evening, Elrond managed to distract Erestor long enough to slip a potion into his wine goblet, and once Erestor had downed the doctored beverage, he slipped into a deep sleep. Elrond then summoned Glorfindel, and the two of them contrived to gently carry Erestor to his chamber and put him to bed. Erestor slept away the entire night and the following day and did not awaken until the next evening. He was of course absent from several meals, and at one of them Elrohir and Elladan brought up the incident with Aragorn.
"Aragorn," said Elrohir, "you had probably better show us where Erestor found that mushroom."
"Yes," Elladan chimed in. "Then, if any others crop up, we'll take care of them."
"Of course," agreed Aragorn. "How lucky it is that you two are willing to see to this matter."
Elladan and Elrohir inclined their heads gravely in acknowledgement of the compliment, while Legolas shook his head and rolled his eyes. That human was so young sometimes!
As for Elrond, his famous eyebrows shot up nearly to his hairline. Still, for all Aragorn's naiveté, it must be acknowledged that the Ranger never, ever, made another mistake when it came time to distinguish poisonous mushrooms from wholesome ones.