The tents were up, sleeping bags laid out, and supper finished. The humid August air seemed nearly as wet as the river we had paddled that day.

My co-leader Charlie and I were in charge of a dozen adolescents who had signed up for an overnight camping and canoeing class called "Backwater Adventures." Our classroom was the St. Croix — a federally designated Wild and Scenic River that delineates a serpentine border between Minnesota and Wisconsin.

We all cleaned up the supper dishes and strolled to a gravel bar where the river’s current swept by. Charlie couldn’t resist picking up his fly rod to inventory the river’s fish population. After a few false casts, his woolly bugger fly enticed a hefty smallmouth bass to strike. I don’t know who was more excited, Charlie or the youngsters. He released the fish and suddenly half the crew claimed the remaining five fly rods.

The other boys stood without fishing rods at my side. I picked up a nearby plant press and carefully lifted the layers of blotting paper to show the boys the flattened and dried plants collected earlier. It seemed a tall order to compete with a broad river muscled with hungry smallmouth. Anyone with sense would put their money on the bass over a dried, dead plant. But I knew that if I could tell a dramatic story about a particular bit of stem, leaf, and flower, I had a chance of grabbing their attention.

The setup was easy.

I asked the lackadaisical boys, "Any of you seen the ‘Indiana Jones’ movies?" (Given that this evening happened a score of years ago, I was confident that they were all familiar with the hair-raising adventures.) All of them raised their hands and some started sharing favorite scenes. But then I stopped them in their tracks.

"What if I told you that Indiana Jones was a wimp compared to the early plant collectors of the 18th and 19th centuries?" Now they wanted to know more.

I went on to tell them that men of science often accompanied early explorers on journeys from Europe to exotic lands across the seas. The scientists would have carried plant presses very similar to the one I showed the boys. The boys were transfixed when I shared that many plant collectors were killed or injured from shipwrecks, unknown diseases, and attacks from natives and wildlife.

We collected a goldenrod and I showed them the proper way to position the plant for pressing. I explained the need to write notes as to the location, date, and description of the habitat where the plant was collected.

It was then that one of the boys asked the question that would give birth to an adventure: "Are there any rare or unusual plants around here?"

I answered, "Well, about a half-mile upriver, I recall finding a nice clump of showy lady slippers." I explained that this lovely orchid is the Minnesota state flower.

Suddenly angling was forgotten and the boys wanted to be plant collectors going into the unknown. They begged, "Can we go look for them?"

I expressed my concern that we had only an hour or so of sun left before darkness settled in. And given that there was no trail, I wasn’t sure if we could make it. My hesitancy only fueled their desire. Soon we were scrambling up the steep river slope to bushwhack upriver. We were on a mission.

It didn’t take long to work up a sweat as we traversed wooded ridges. We encountered a series of seeps that sucked our footsteps into the shin-deep black muck. And then the thick stands of wood nettles that burned our exposed skin. As the sun dipped below the horizon, the mosquitoes began their bloodletting of our sweaty bodies.

Finally, we found the small draw I had been seeking. There were three clumps of spectacular orchids in bloom. I explained that there are laws that prohibit collecting certain plants and that we could only look at these showy lady slippers.

After inspecting the orchids, we thrashed through the tangle of willows to the river’s edge to splash our itching bug bites and nettle rashes and wash the muck off our legs. Standing in the shallows, we looked wistfully downriver and could see a lively campfire flickering in the distance. Charlie and his crew of anglers were relaxing around the fire. It looked so welcoming and yet so far away.

I said we’d better hurry back. The boys paused. "We don’t have to go back the same way, do we?"

"No choice," I responded.

Then one of the boys (inspired by the excursion) suggested, "Why don’t we roll a log into the river? We can hang on to it as we float down to camp."

I didn’t have time to respond before another boy said, "That would be cool! We could float real quiet and sneak up on the guys at the fire and scare them!"

My retort was short and pathetic. "We can’t. We don’t have life jackets and we have a plant press with specimens."

The debate was unfair as the five boys problem solved and argued against my sole policy-correct position. One boy blurted, "We can get two logs, make a platform out of sticks, and wrap the plant press in our shirts and set it on the raft."

I was amazed at how fast my inner-boy got excited about the endeavor, but my leader responsibilities still bore down hard. Less than a half-minute passed and I relented.

"You guys have to absolutely promise to hang on to the log! There is a deep stretch we have to go over and if any-thing bad happens, I will lose my job and maybe worse."

It took less than five minutes to find a couple of hefty, dry cottonwood limbs and roll them into the river. Several boys donated their shirts to swaddle the plant press, which was perched in a secure spot on the branchy barge. Then we waded into the cool, dark river, hugged the beefy limbs, and let the slow current carry us. Over the course of our twenty-minute float, the boys whispered about creeping out of the water, commando style, and popping up at fireside to scare the others.

One of the boys, Brock, had been a little nervous about getting his clothes wet and getting into the moving river. I made sure to place myself next to him.

As part of the river’s flotsam, we slowly drifted closer to camp. I tried to dismiss the fact that I couldn’t touch bottom. We were about halfway to camp when Brock whispered, "Look! Look at all the stars floating on the water!" Our small crude raft was surrounded by the twinkling reflection of a sky full of stars.

"Shhhh," someone whispered. "We have to surprise them." And so we did.The soaked squad of little commandos burst out of the tall grass, surprising the wide-eyed campfire loungers.

I told the boys to go to their tents and change into dry clothes and come back to the fire. Ten minutes later, both crews of boys shared tales of collecting plants and catching fish.

Brock, the tentative explorer, spoke the words that have stuck indelibly with me since that memorable night. He smiled broadly into the campfire’s leaping flames and said, "I’ll never forget this night as long as I live. Someday I’m going to write about this."

So in the end, the risk was worth it. Because if Brock remembers that event over a score of years ago, he could very well be raising a child and sharing the story of that night when the stars floated downriver. With luck, Brock will help create spontaneous outdoor experiences that will serve his children and our world for a long time.

The irony is that while Brock enthusiastically declared his need to write about the evening adventure, here I am typing a memory that turned out to be one of the defining moments of my career as a professional naturalist. And yet very little of that magical evening was planned.

The most memorable and poignant experiences tend to be those that are enthusiastically spontaneous. As adults interacting with youth, we only need to cultivate the possibility of such indelible, spontaneous experiences.