Posts Tagged ‘rock tripe’


A couple of weeks ago, RailGuy and I headed up to Arnprior, north and west of Ottawa, to hike the Macnamara Nature Trail. The trailhead is just outside downtown Arnprior, in an industrial area. The trail runs in part through the property of Nylene Canada Inc. At the trailhead, you can pick up a helpful guide. It highlights 19 stops along the trail with information about the natural and human history relevant to each location.


The four kilometre long trail (five if you include the optional sidetrail to the marsh lookout) is well-marked and nicely maintained, with benches thoughtfully placed at the top of a few modestly demanding climbs. Near the trailhead, there was quite a bit of traffic and commercial noise, but we weren’t far along the trail before the sounds of industry fell away and the quiet of the forest prevailed. Comprised mostly of deciduous trees, the woodland is open and pretty.


A section of the trail travels through the upper reaches of the wetland and features a sturdy boardwalk. At the edge of the boardwalk, we spotted the red berries of Jack-in-the-Pulpits (Arisaema triphyllum). You can readily see the source of its scientific name, three-leaves, triphyllum.


The remains of an old lime kiln provide evidence of early industrial activity in the forest. The kiln was built by the McLachlin Lumber Company in the mid-to-late 19th century. The rocky ground, part of the Canadian Shield, is mainly marble and limestone. The igloo-like kiln was stocked with firewood and used to heat broken chunks of rock. When water was added to the burnt rock, it produced slaked lime (Calcium hydroxide), a product used as mortar in brickwork or as paint (whitewash).


Not far from the lime kiln remains, a set of stairs allows hikers to get a close-up look at the rock face.


There are a few points of interest here. In the little den formed by the facets of rock, there are piles of oval droppings. They are evidence that the den has been popular with porcupines over many years.


But the main attraction is the colony of rare Walking Ferns (Asplenium rhizophyllum). Their name is derived from the manner in which they reproduce. Whenever the long, pointed tip of a leaf-like frond touches down, a new frond can sprout up. A parent plant can thus create several generations of fronds via vegetative reproduction as it ‘steps’ across the rock. Walking Ferns are calciphiles, lovers of calcium-rich soils. Walking Ferns can be found in shady spots on limestone ledges and in limey forest places.


The rock also features a foliose lichen, perhaps an Umbilicaria species, known as Rock Tripe.


Back on the main trail, I notice this burl, or burr, high up on a tree. It looked for all the world like a small animal with its limbs wrapped around the tree. Burls are tree growth in which the grain has grown in a deformed manner. They are the result of some sort of stress suffered by the tree, perhaps from an injury, virus or fungus.


We followed the sidetrail to the marsh lookout. To the east, the wetland is more marshy, while to the west, it is swampy, with trees growing into the wet area. Off in the distance, you can just make out Goodwin’s Bay and the Ottawa River. The marsh floods in the spring when the Ottawa River rises, carrying a flush of nutrients into the wetland.


There were splashes of bright yellow flowers sprinkled through the wetland, Nodding Bur-Marigolds (Bidens cernua).


There was quite a bit of diversity in the forest groundcover. Some areas of the forest floor were dressed in a variety of ferns, while other regions featured a groundcover of club moss. One section of the trail was bordered by the heart-shaped leaves of Wild Ginger (Asarum canadense).


When we came to a stand of Eastern Hemlock trees, we looked for the work of Yellow-bellied Sapsuckers. We had a family of sapsuckers nest in a large, old maple tree this summer, and I often saw them flitting about the garden, where their preferred tree to tap was a little locust. I didn’t know that sapsuckers are partial to hemlock trees until I read it in the guide. Sure enough, the neat rows of sap wells that the sapsuckers drill were readily apparent.


After passing through the hemlock grove, we continued back to the parking lot. These are just some of the highlights of our hike. The Macnamara Nature Trail was named after Charles Macnamara (1870-1944), a naturalist and photographer who loved these woodlands. A gifted amateur, he identified six species of springtails (Collembolans), and one species is named after him. The trail is a wonderful memorial to Macnamara. The guide book, provided by the Macnamara Field Naturalists’ Club, really enhances visitor understanding and enlivens the hike. This was one of our favorite hiking trails, and it is well worth visiting.


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It’s easy to miss lichens during the summer. At least here in the north, they have to compete with the riotous growth of green plants that have only a few short months to do their thing. Lichens really come into their own in winter, when the bare landscape lets them shine. When I was hiking a few weeks ago, lichens were among the most eye-catching subjects along the trail. Suddenly, with the trees bare of leaves, lichens are conspicuous everywhere.

When you start looking at them more closely, lichens are fascinating. For starters, a lichen is actually a two-part harmony of a fungal host and an algae. Sometimes a cyanobacteria also plays a role. Some twenty percent of the world’s fungi grow only as part of a lichen partnership. To put this symbiotic relationship very simply, the fungus provides shelter for the algae, while the algae provides food. The fungus benefits more from this relationship. While the algae could survive without the fungus, lichen fungi are never found growing alone.

Lichens grow on a variety of substrates: the ground (including decomposing logs), rocks (including surfaces such as roof shingles) and on trees. The two photos above show examples of a common rock lichen, rock shield lichens of the genus Xanthoparmelia

Rock shield is a foliose lichen, a lichen that looks like leafy growths divided by lobes. The lower surface is often differently coloured from the upper surface. Another example of a foliose lichen found on rocks is Rock Tripe (Umbilicaria spp). Rock tripes feature large, leathery lobes that look like they are peeling off the rock.

Here’s another rock tripe.

I also came across patches of reindeer moss (Cladina spp). It’s not a moss at all, but another lichen. Reindeer lichen is an example of a fruticose lichen, which have bushy or shrubby growth forms. As the name suggests, reindeer moss is an important food source for reindeer and caribou.

Reindeer moss grows over thin soils and rocks. Several different Cladina species may be found growing together.

Lichens that are very flat, appearing to be almost sprayed on a substrate, are termed crustose lichens. Powdery goldspeck (Candelariella efflorescens), which grows in small, round patches, is an example of a crustose lichen. Tree bark may feature whole communities with multiple species of lichens.

Some lichens only grow on specific tree species, while other lichens are generalists. Common greenshield (Flavoparmelia caperata) is a generalist that, as the name suggests, is extremely common.

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