The curious case of escaped quillwort
How eighth-grader Mishka traced lake hedgehog

Eighth-grader Mishka Vasiliev, native of Ust'-Pocha in Kenozero, became maliciously addicted to the sea after he saw Finding Nemo. Spellbound by the vision of the faraway seas, he longs to leave for southern lands. Mishka's growing addition makes his teachers start to worry and tell his parents they should do something: the boy's about to lose his mind.

Mishka's father takes him on a fishing trip. Lines cast, Mishka won't keep silent:

"You call it fish? What fish have we here other than pike and vendace? Oh how I wish I could be at sea now to see its shoals of fish, corals, jellyfish, sea grass. I can't stand seeing this pricky grass or God knows what it is stick out of the water. What is it?

Vexed, he kicks it.

His dad grows indignant.

"You want to know what this pricky grass is? You stupid boy, this is awl-wort. It's other name is quillwort and it is also known as lake hedgehog because of its spikelike leaves. Isoetes lacustris. You know who gave it its name?

Mishka keeps silent. He blushes.

"Great Swedish naturalist Carl Linnaeus. The name is translated from Latin as "identical by state." This underwater hedgehog is an evergreen plant," explained Vasiliev Sr.

Then an idea occurs to him.

"Let me tell you a story, Mishka. A detective one. It's a test. If you solve it by tomorrow, we'll go to Plesetsk on the weekend to get you ice cream. If you don't, you do the Saturday wood chopping.

Here's the story Vasiliev Sr. told his son. Once a group of men were fishing in the lake in Yaroslavl and noticed there was no more quillwort in the water. It was gone. Escaped!

And there were fewer fish to catch. Could the escaped quillwort be involved?
One of the fishermen found a quick solution: while staying in Kenozero that summer, he plucked a quillwort, placed it inside 3 liter jar, brought it home and planted it in that lake in Yaroslavl. But, the quillwort wouldn't take root in its new habitat.

"They said he tried three times, Mishka, that Yaroslavl man. The plant just wouldn't strike root. Why? That is the question I want you to find the answer to."

Mishka goes home and spends the night searching books and surfing the net for the answer. He learns a lot of interesting things. That quillwork turned out a hard nut to crack. Firstly, it's as old as dinosaurs. Secondly, millennia ago it moved from wetlands into lakes. Thirdly, despite being a benthic species, it reproduces by spores like mushrooms do. Fourthly, it is globally endangered and is listed in the Red Book of Russia. That Yaroslavl fisherman broke the law by putting his quillwork in a jar. And fifthly...

"Dad, wake up! I've got the answer! The quillwork is an indicator species. It grows only where it's clean, where the water is ecologically safe. The lake it has escaped from is where they built a factory. The factory is the reason why it, and the fish and the quillwort from Kenozero have all disappeared.

"I promised you ice cream, I'll get you ice cream," says his dad.

There was one more thing Mishka understood but he kept it to himself. He was wise enough to realize the reason why his dad told him that story. He wanted his son to see that Kenozero Lake contained just as many, if not more, mysteries as the faraway southern seas. If quillwort had to settle here in pursuit of purity, it's a shame for a human being to stay blind to what even plant appreciates.