These Lichen Are Likin' My Fence

The ongoing repairs to my fence have given me another opportunity for observing nature. The strange object above is a British Soldier Lichen. These were growing in several places on my fence. This is an extreme close up - they are at most only a few millimeters high.

Lichen are a symbiotic living arrangement between a fungus and an algae. The algae provides food for the fungus through photosynthesis, and the fungus provides minerals from the environment and shelter for the algae.

The lichen takes its scientific name from the name of the fungus. In this case, a Cladonia cristatella fungus is co-habitating with a Trebouxia erici algae. What is amazing is that the fungus by itself is a white blob, and the algae by itself is a green blob. Only when they are living together do they form the stalk (thallus) with the bright red fruiting structure (apothecia) on top.

This one appears to have a few white dots on the fruiting structures. I noticed this on some photos of other British Soldiers on the internet. Nobody mentioned what these are, but I have to guess they are spores getting ready to be released. The spores are only from the fungus - the "offspring" will not form lichen unless it comes across the proper algae.


This next one, I believe, is a Beard Lichen (Usnea sp.). This lichen is well known for its antibiotic properties. Before the invention of "modern" antibiotics (derived from Penicillium fungus), Usnea lichen was placed on wounds to keep them from getting infected. If you are a Lost fan and were wondering what that "stuff" was being draped on Jacob's mother's wounds, it was probably Usnea lichen.

Unfortunately I can't be completely sure that this lichen is Usnea sp. Some other lichens look similar. If you are stranded on a desert island with an open wound and you need to know for sure, apparently the trick is to break the stalk (thallus). If there is an elastic, white cord running down the center, it is Usnea. (This bit of medical advice is from Wikipedia. You might want to consult a trained ethnobotanist before becoming stranded on a desert island.)


Finally, this somewhat boring lichen is a Common Greenshield (Flavoparmelia caperata). Hey, not every lichen can be interesting or beautiful. The wrinkly part in the middle releases "soredia", which are bits of fungus wrapped around bits of algae. These will grow new lichen when they are released, as opposed to the "spores" released by the British Soldiers which grow only fungus.

One thing I can tell you about removing lichen - if you are allergic to fungus (aka mold) you should wear a dust mask. My nose is still running and I am still sneezing.

See this link for my last adventure fixing the fence.

Hairy Brown Creature

As I was outside repairing our fence gate last night, the above creature entered our open back door. Is this creature:

a) Chewbacca the Wookiee?
b) Bigfoot?
c) A tribble from the Star Trek episode "Trouble With Tribbles"?

You decide:


Maybe a different view of this creature would help:


This view really gives it away:


If you haven't guessed by now, it is a moth:


I'm not sure what type of moth this is, but my best guess is some type of Tiger Moth. I found some species of Tiger Moths in books and online that look pretty similar to this one.

I was feeling bad that I couldn't determine exactly what species mine was, but then I came across this great quote from an experienced lepidopterist on ButterfliesAndMoths.org, confirming the difficulty of identifying moths - "If it ain't 'pretty' in some way, but just another brown fuzzy one, I wouldn't have a clue!"

I happen to think my fuzzy brown moth is pretty in some gross way, but that website did make me feel better about not being able to identify it. If you know what it is, please leave a comment!

[Update 6/24/10: I have finally identified this guy. He is an Eastern Tent Caterpillar Moth. My insect field guide has a photo of a Western Tent Caterpillar Moth, which has a similar hairdo but no stripes and smooth antennae. On a hunch, I looked for photos of other types of Tent Caterpillar Moths on the internet, and I found the Eastern.]

Wild Flax

I finally got around to buying myself a wildflower field guide, so I can start identifying the many flowers I have come across and photographed over the years.

Of course this has turned out to be much harder than I thought it would be. Like birds and insects, wildflowers also have too many species to fit into a practically sized field guide. Like birds and insects, wildflowers can also look different at different times of the year or at different stages of their lives, and can look different in different parts of the country. Wildflowers can also have completely different colors within the same species.

But I am pretty sure the flower pictured above is Wild Flax (Linum lewisii). I found it in Red Rocks Park outside of Denver. Actually, the common name of this flower is Wild Blue Flax, but since it can also be found in white, yellow and red, I am going to simplify things for us wildflower newbies and just call it Wild Flax.

I was lucky to find such a bright blue specimen - the photo in the field guide and most of the photos I found online were pale blue. What gives it away as Wild Flax are the shape and number of petals and stamen (5 of each), the shape and color of the veins in the petals, the linear shaped leaves, and the drooping stems.

Wild Flax is the untamed uncle of Common Flax, the crop plant that gives us linen fibers, flax seed, and linseed oil. Here is a cross-sectional photo of a flax stem from Wikimedia. The white fibers just inside the outer layer (marked "BF") are the "bast fibers", which are used for making linen.


Bast fibers are the fibers that give structural support to the stems of some types of plants. Through a series of physical and chemical processes, the bast fibers are removed from the rest of the stem. Here is what the bast fibers look like (also from Wikimedia), ready to be spun into linen:


Linen is believed to be the first plant fiber used for making fabric, about 30,000 years ago. I think it is amazing that our ancestors figured out how to do this.

I can understand them making clothing out of fur or wool, since they saw how it kept animals warm. And I can understand why they would eat certain plants, possibly after watching animals safely eat them. But to look at a beautiful blue flower and say, "I bet I can extract the fibers from that stem and make myself a loincloth" is a great intellectual leap. We all owe that person a debt of gratitude!

Patience Pays Off for Pothole Populations

The photo above may not look like much, but it took hundreds of years to create. It is a pothole in the bedrock of Mather Gorge, which I saw on my recent trip to the Great Falls of the Potomac.

The red lines I drew show the general shape of the "pothole". The blue chicken scratch was my attempt to show water swirling inside, carving out the pothole. About 35,000 years ago, during the Wisconsin Glaciation, huge amounts of melt water from the glaciers poured through the Mather Gorge. The spot where I was standing to take this picture was under water.

A turbulent vortex of water, created by some obstacle such as a rock, started spinning above the future location of this pothole. The swiftly flowing water carried sand and stones, which acted like sandpaper against the bedrock. Over hundreds of years, a circular pothole was formed.

In the thousands of years since, weather and water have caused the large crack at the back of the pothole, and completely ripped off the front half. What you see is half a pothole.

The above photo is the largest pothole I came across. It was about 5 or 6 feet deep. There are many potholes along both banks and on the islands in the river. Here is a top view of a small one, only about a foot across. It became filled with silt over the years.


Where the rock is softer, it gets eroded much quicker, and can form very large potholes. The pothole below is in Moab, Utah. The photo is from the Utah Geological Survey.

As you can see, if the pothole has not cracked or been filled with silt like the ones I saw, it will hold water. This pothole in Utah is in a dry area, and the water at the bottom is rain.

Amazingly, organisms have adapted to live in these transient pools of rainwater. They include mites, nematodes, tardigrades, and many others. The conditions in the pools are harsh, with wide temperature variations including freezing of the water during the winter. Oxygen and pH levels also swing widely. The smaller pools periodically dry up completely.

Some residents of these potholes, or at least their eggs, have been known to live dormant for many years without water. Some of these organisms are so well adapted to their harsh environments that they have not changed in millions of years. Their ability to withstand these conditions makes them of great interest to scientists looking for life on other planets. Click here to read more about this in NASA's Astrobiology Magazine.