Just 4 miles due south of Terwilliger Hot Springs, Hidden Lake has become a popular destination in the Cougar Reservoir area. During the recent NPSO Annual Meeting last month, there were two trips offered to botanize at Hidden Lake. Since I was leading hikes elsewhere (see Field Trip Highlights from NPSO Annual Meeting), I didn’t go on either of those, but I hadn’t been there for years, so I thought it was about time to go back. And after noticing some other wetlands not too far from the lake, I was even more intrigued and headed out there on August 7.
Unfortunately, that day was a Sunday, and the lake was particularly noisy with excited children. Adults were also swimming and jumping off a trampoline that is attached to a dock out in the middle of the lake. That actually looked like fun, but it was a little cool, and I wasn’t prepared to swim—another time perhaps. While everyone else was focused on the lake itself, I was more interested in the bog that lies along the northeastern edge of the lake. Although I hadn’t thought to bring a bathing suit, I was prepared with rubber boots. What I hadn’t remembered was that this is a floating bog. I carefully walked along the edges, but I didn’t feel comfortable going out into the center. The bouncing effect wasn’t that different from the trampoline! And after my recent fall into a deep hole at Quaking Aspen Swamp (see Highs and Lows at Quaking Aspen Swamp), I really didn’t want to break through. I’m still mourning the loss of my camera that got irreparably damaged during my quick dunk there and did not want a repeat of that.
Treading carefully along the edges, I was able to see lots of round-leaved sundews (Drosera rotundifolia) and hooded ladies’ tresses (Spiranthes romanzoffiana) in the thick sphagnum. Two mint family species, purple-flowered field mint (Mentha canadensis) and white-flowered northern bugleweed (Lycopus uniflorus), were in bloom, along with late-blooming creeping buttercup (Ranunculus flammula) and western water hemlock (Cicuta douglasii). There were also a number of graminoids, including the unusual and uncommon threeway sedge (Dulichium arundinaceum) that I had just seen the week before (see Hidden Gem Near Kwiskwis Butte), and mud sedge (Carex limosa), with its pretty dangling inflorescences.
With all the hubbub at the not-so-hidden Hidden Lake, I was ready to get away from the crowds (including a visit from a state police trooper—that’s a first for me while out botanizing!) and headed off to go find the two really hidden lakes across the road to the north of the main lake. The road is now blocked off past the parking site for the lake, but after only a short walk past the blocking boulders and around the corner, I headed into the woods where an old road sign indicated a former road that once went between the two small lakes. The old road bed had filled with smaller trees, so I just headed out through the woods, armed with my aerial photo.
The first lake was only 300′ or so from the road. It was a good thing I had my boots on because even in August it was quite wet around the edges and didn’t have a very well defined shoreline. There were lots of interesting aquatic plants in the water, but I had a hard time getting close enough to get a good look at them. With binoculars, I could make out some lingering flowers on a narrowleaf bur-reed (Sparganium angustifolium), old yellow pondlilies (Nuphar polysepala), and maybe some kind of pondweed (Potamogeton sp.). More threeway sedge and other true sedges (Carex spp.) filled in the transition area between open water and (semi)solid ground. On the south side, there was a small mossy bog with round-leaved sundews and tiny-flowered Oregon willowherb (Epilobium oregonense). Western oxypolis (Oxypolis occidentalis) was in full bloom here and underneath numerous shrubs growing along the edges.
Although the second hidden lake is only about 500′ from the first one, going over numerous logs and through tangles of rhododendrons—all in rubber boots—made it seem farther than that. It was also quite shallow and filled with plants, but there weren’t quite as many interesting ones as the first little lake, and there was no bog or sundews. I only stayed a short while looking at one shore before heading back to the road. Before heading home, I made a few quick stops at nearby sites I’d seen on Google Earth. The first was another nearby lake, but I decided it didn’t look promising enough to warrant going down a steep bank to get to it. The latter didn’t seem terribly interesting and didn’t seem like it had much herbaceous wetland. It was mostly choked with willows and hardhack (Spiraea douglasia). I took a quick walk out on a log over the shrubs and then turned back. When I talked to John Koenig about this trip later, I discovered this last spot was where the rare northern adder’s-tongue (Ophioglossum pusillum) had been found—a plant I’ve never seen before. Guess I should have given the spot a better look!